Communicating climate change has never been so important, and this IPCC report pulls no punches

Simon Torok, The University of Melbourne; James Goldie, Monash University, and Linden Ashcroft, The University of MelbourneOn Monday, the Intergovernmental Panel on Climate Change (IPCC) released the first instalment of their sixth assessment report. As expected, the report makes for bleak reading.

It found all regions of the world are already experiencing the impacts of climate change, and its warming projections range from scary to unimaginable.

But the report also makes for dry reading. Even the Summary for Policymakers, at 42 pages, is not a document you can quickly skim.

Local governments, national and international policymakers, insurance companies, community groups, new home buyers, you and me: everyone needs to know some aspects of the IPCC’s findings to understand what the future might look like and what we can do about it.

Read more:
This is the most sobering report card yet on climate change and Earth’s future. Here’s what you need to know

With climate action more crucial than ever, the IPCC needs to communicate clearly and strongly to as many people as possible. So how is it going so far?

The most assertive report in 30 years

The gruelling IPCC process and an extensive author list of 234 scientists make IPCC reports the world’s most authoritative source of climate change information. Every sentence is powerful because each one has been read and approved by scientists and government officials from 195 countries.

So when the report states “it is unequivocal that human influence has warmed the atmosphere, ocean and land”, there is absolutely no denying it. In fact, the IPCC has become progressively more assertive in the 30 years it has been assessing and summarising climate science.

In 1990, it noted global warming “could be largely due to natural variability”. Five years later, there was “a discernible human influence on global climate”. By 2001, “most of the observed warming […] is likely to have been due to the increase in greenhouse gas concentrations”.

This week’s reference to “unequivocal” human influence pulls no punches.

Why has this language changed? Partly because the science has progressed: we know more about the complexities of the Earth’s climate than ever before.

But it’s also because the report’s authors understand the urgency of communicating the message effectively. As this week’s report makes clear, limiting warming to the most ambitious 1.5℃ goal of the Paris Agreement may be (at least temporarily) out of reach within decades, and the goal of keeping warming below 2℃ is also at risk.

As the IPCC’s scientific assessment reports are only published every seven years or so, this may be the authors’ last chance to warn people.

Climate change communication isn’t easy

Communicating any science is hard, but climate science has particular challenges. These include the complexities of the science and language of climate change, people’s misunderstanding of risk management, and the barrage of deliberate misinformation.

The IPCC has standardised the language they use to communicate confidence: “likely”, for example, always means at least a 2-in-3 chance. Unfortunately, research has shown this language conveys levels of imprecision that are too high and leads to readers’ judgements being different from the IPCC’s.

The gruelling report approval process also means IPCC statements can be conservative to the point of confusion. In fact, a 2016 study showed IPCC reports are getting harder to read. In particular, despite the IPCC’s efforts, the Summaries for Policymakers have had low readability over the years, with dense paragraphs and too much jargon for the average punter.

Thermometer on the right marks increments of 0.1 °C, with 1.1 °C (the current warming level, 1.5°C and 2°C highlighted. Infographic equates 5 years of global emissions at the 2019 rate or 42 billion tonnes of CO2 to 0.1 °C of warming.
Condensing the IPCC report to its highlights, such as in this graphic, is an effective way to engage time-poor readers.
Monash Climate Change Communication Research Hub/IPCC

There has also been a rise in communication barriers since the final part of the IPCC’s Fifth Assessment Report was released in 2014, including more fake news, and climate news fatigue.

The IPCC’s complex results can appear controversial and hotly debated, because of politicisation and a well-funded disinformation campaign from fossil fuel giants. And with news so often passed through social media, it’s easy for people to turn to someone they trust, even if that person’s information is wrong.

Read more:
Fossil fuel misinformation may sideline one of the most important climate change reports ever released

While there has been an increase in communication imperatives, including the urgency for action and the increase in science information, these are all taking place during a headline-stealing global pandemic.

Also, people are exhausted. Eighteen months of living with a pandemic has probably shrivelled everybody’s ability to take on more big problems.

On the other hand, hunger for COVID-19 information has raised familiarity with exponential curves, model projections, risk-benefit calculations, and urgent action based on scientific evidence to combat a global threat.

Remaining hopeful

To address the challenges of communicating the science, climate communicators should aim for consistent messages, draw on credible information, focus on what is known rather than the uncertainties, offer tangible action, use clear language that avoids despair, connect locally, and tell a story.

To a large extent, Australian contributors to the IPCC release this week have done just that, chiselling relevant facts from the IPCC’s brick of a report into blogs and bites.

To its credit, the IPCC has also provided a plethora of communication resources in different formats. This includes videos, fact sheets, posters and, for the first time, an interactive atlas enabling you to explore past and possible future climate changes in any region.

However, there’s (so far) less focus on information for different audiences, such as students, young people, managers and planners rather than just politicians and scientists.

And the atlas, while a great tool, still requires users to have some climate science literacy. For example, average users looking for future climate information may not understand that CMIP6 and CMIP5 are the next, and previous, generations of climate models used by the IPCC.

While mainly focusing on the report’s terrifying findings and commitment to global warming, media coverage this week also emphasised the importance of immediate action, and sources of hope.

This is a positive approach because feeling that humanity cannot, or will not, respond adequately can lead to a lack of engagement and action, and eco-anxiety.

As Al Gore pointed out 15 years ago in An Inconvenient Truth:

there are a lot of people who go straight from denial to despair without pausing on the intermediate step of actually doing something about the problem.

Early next year, the IPCC will release two volumes about ways to adapt to, and reduce, climate change. After the confronting results of this first volume, the next two must provide messages of hope if we’re to keep fighting for our planet.

Read more:
Australians are 3 times more worried about climate change than COVID. A mental health crisis is looming

Click hereto read more of The Conversation’s coverage of the IPCC reportThe Conversation

Simon Torok, Honorary Fellow, School of Earth Sciences, The University of Melbourne; James Goldie, Senior Knowledge Broker, Monash University, and Linden Ashcroft, Lecturer in climate science and science communication, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Fossil fuel misinformation may sideline one of the most important climate change reports ever released


Christian Downie, Australian National UniversityThis week’s landmark report on the state of the climate paints a sobering picture. The Intergovernmental Panel on Climate Change (IPCC) concluded that, without deep and immediate cuts to greenhouse gas emissions, the world is very likely headed for climate catastrophe.

In November, world leaders will gather in Glasgow for the latest round of United Nations climate talks. It’s the most crucial round of climate negotiations since those which led to the Paris Agreement in 2015.

The question is: will governments around the world now listen to the climate science? Or will misinformation campaigns backed by vested interests continue to delay action?

If we’re to avert a climate disaster, we must not underestimate the power of climate misinformation campaigns to undermine the IPCC findings and ensure governments continue to ignore the science.

Person in crowd holds sign
Science must be at the heart of policy-making if climate change is to be addressed.

A history of heeding the science

Scrutiny of Australia’s climate policies will be particularly harsh at the Glasgow meeting, given the Morrison government’s failure to implement substantive policies to reduce emissions. We can expect renewed international pressure on Australia to commit to net-zero emissions by 2050 and set out a national plan to decarbonise the economy this decade.

For those who believe in the power of science, the failure of world leaders to act urgently is frustrating, to say the least.

We have acted on the concerns of scientists in the past. In fact, it was scientists such as NASA’s James Hansen who put climate change on the agenda back in 1988, triggering international negotiations.

Scientific concern over the growing hole in the ozone layer prompted the 1987 Montreal Protocol, an international agreement to curb the use of ozone-depleting substances.

And of course, scientific advice is guiding the government response to the COVID-19 pandemic.

There are many reasons why the calls of climate scientists are not being heeded at present. But one factor has been particularly successful in delaying climate action: scientific misinformation campaigns.

These campaigns damage public understanding of science, erode trust in research findings, and undermine evidence-based policy.

Read more:
A brief history of fossil-fuelled climate denial

Earth from space
Governments heeded scientific warnings over the ozone hole – so why not climate change?

Muddying the waters

Research has shown climate misinformation campaigns are often backed by corporate interests which stand to lose if the world transitions to a cleaner energy future.

Such a future could bring incredible benefits to Australia – a country with some of the world’s best solar and wind resources.

The campaigns have wrought untold damage to the public debate on climate science. These corporations have funded industry associations, think tanks and front groups (even including paid actors) to mobilise a counter movement to climate action.

Examples of the phenomenon abound. In the United States, oil and gas giant ExxonMobil reportedly knew of climate change 40 years ago, but funded climate deniers for decades.

Reports emerged last week that Facebook failed to prevent a climate misinformation campaign by the oil and gas industry during last year’s US presidential election.

The war against climate science has been waged in Australia, too. Researchers and journalists have described the lengths the oil, gas and coal industries have gone to challenge the scientific consensus on climate change, and to kill off policies put in place to limit emissions.

Australian media companies such as News Corp have also been criticised for downplaying the significance of the climate crisis. Little wonder, then, that Australian news consumers are far more likely to believe climate change is “not at all” serious compared to news users in other countries.

Read more:
With the release of a terrifying IPCC report, Australia must face its wilful political blindness on climate

man holding sign reading 'Tell the Truth'
News Corp has been accused of underplaying the seriousness of climate change.

Calling out misinformation

The latest IPCC report was five years in the making. It involved 234 leading scientists from more than 60 countries, who rigorously assessed more than 14,000 research papers to produce their synthesis. The result is the most authoritative, reliable report on the state of Earth’s climate since the last IPCC report of its kind in 2013.

But as the history of climate action has shown, incontrovertible science is not enough to shift the needle – in large part due to climate misinformation which deceives the public and weakens pressure on governments to act.

We must call out attempts by those who seek to delay climate action in the name of profit – and then counter those attempts. As the IPCC has shown this week, further delay equals catastrophe.

Read more:
We have the vaccine for climate disinformation – let’s use it

The Conversation

Christian Downie, Associate professor, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

With the release of a terrifying IPCC report, Australia must face its wilful political blindness on climate

Lukas Coch/AAP

Mark Kenny, Australian National UniversityI remember the acute frustration of watching one of the US news feeds on September 11, 2001 — 20 years ago next month.

With the stricken twin towers smoking away in the background, the news anchors described the heroic rescue mission going on behind them, continuing for several excruciating moments after one tower had simply ceased to exist — a fact terrifyingly obvious to viewers.

“It’s gone” I yelled at the TV helplessly, “there is no rescue!”.

Read more:
This is the most sobering report card yet on climate change and Earth’s future. Here’s what you need to know

The other building would soon follow as the full horror went from unimaginable to undeniable in a single morning.

Many Australians feel a similar frustration – this time chronic – at the refusal of their government to “turn around” to face what’s clear to everyone else, a galloping climate emergency which portends death, suffering and species loss on a planetary scale.

Yet, as the evidence has accumulated, and the new IPCC report reinforces it, Australia has carved out a name for itself as a global laggard — grouped with denialist authoritarian states like Russia, China, and Saudi Arabia.

And it has done so by re-interpreting the global climate evidence as just another domestic political argument – an opportunity for creating winners and losers and profiting from the electoral dividends yielded.

The 2050 pantomime

Ever wonder why an Australian political class steeped in short-termism is so animated about 2050 — a date way beyond the horizons of those currently in power?

Partly it is because if an economy is to genuinely commit to emitting net-zero carbon by 2050, the hard work of adjustment needs to commence immediately. But mostly it is that 2050 has become a useful distraction from the here-and-now.

Barnbaby Joyce at the despatch box
Barnaby Joyce’s return to the Nationals leadership has not helped Australia’s progress on climate change.
Lukas Coch/AAP

And it is on this faux battleground that Prime Minister Scott Morrison has excelled in restricting not just his own rhetorical manoeuvrings, but increasingly, those of his opponents. Indeed, Morrison has achieved a remarkable double by simultaneously reducing 2050 to mere symbol, while also framing it as the only battleground on which the climate contest can be fought.

This way, he either wins, or he doesn’t lose, because the stakes are rendered so distant and so low as to not affect voting preferences appreciably.

From waving a lump of coal to Glasgow

Since appearing at the National Press Club in February 2021, the man who once brandished a lump of coal in parliament has moved to assure voters he now wants Australia to get to net-zero “as soon as possible, and preferably by 2050”.

Read more:
Climate change has already hit Australia. Unless we act now, a hotter, drier and more dangerous future awaits, IPCC warns

Though intentionally vague, this putative hardening from merely “as soon as possible” was treated as progress by many in the press gallery, which is arguably too aware of Morrison’s partyroom arithmetic and thus overly inclined to see the climate challenge as his rather than the country’s.

(This is this same commentariat, by the way, that gave Morrison an unequalled level of authority inside the partyroom following his “miracle” election victory in 2019.)

Since that February address, most observers have assumed Morrison would find a way to get his government to the 2050 commitment ahead of the Glasgow COP26 summit in November. That would mean strong-arming climate-sceptic Liberals, as well as the much harder task of wrangling the Nationals.

The Joyce factor

But if anything, that task has steepened in recent months with the election of Barnaby Joyce as Nationals leader and deputy prime minister.

As Joyce (speaking in the third person) told the Australian Financial Review in July:

The likelihood of Joyce getting endorsement from his party room to agree to net zero is zero.

And if Joyce was to come back to the party room and said ‘I had a really interesting conversation, I’ve just agreed to net zero’, then his prospects of getting out of that room as a leader would be zero.

That such unvarnished self-interest flies as a legitimate policy argument says everything about the vapid quality of the climate change debate in Australia.

Labor’s retreat

In truth, Morrison is comfortable keeping the argument on 2050 anyway, knowing the date is as abstract and intangible to many voters as the dangerous build-up of atmospheric carbon dioxide is visible to the naked eye.

And why not? Labor has already retreated from its last election pledge of a 45% cut by 2030, hounded into meekness by Morrison’s 2019 scare campaign alleging runaway job losses and lower economic growth from Labor’s rapid adjustment.

Labor leader Anthony Albanese.
Labor is set to reveal it’s new climate policy ahead of the next federal election.
Lukas Coch/AAP

Labor’s new policy will be unveiled closer to the election, but it is not expected to be as ambitious, even though since 2019, the rest of the developed world has embraced targets at or beyond this scale.

In a sign a milder policy is in the offing, Labor insiders plead the previous 45%-by-2030 policy had been set in the middle of the last decade and that commencing that reduction from 2022 is unrealistic. Yet, the first IPCC report for seven years warns the 1.5℃ warming threshold will now be reached as early as 2040, which probably means Labor should, in fact, propose to go harder.

There’s no sign of the government going harder either. Asked on Tuesday if Australia would set out more ambition in light of the IPCC warning, Morrison said,

we need more performance, we need more technology, and no one will be matching our ambition for a technology-driven solution.

It was an answer perfectly consistent with his past mantra of “technology, not taxes”.

Thus, it was also an answer that was perfectly inconsistent with the facts set out by the world scientific community. Facts to which Australia is yet to turn its full face.The Conversation

Mark Kenny, Professor, Australian Studies Institute, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

IPCC says Earth will reach temperature rise of about 1.5℃ in around a decade. But limiting any global warming is what matters most

Dave Hunt/AAP

Michael Grose, CSIRO; Malte Meinshausen, The University of Melbourne; Pep Canadell, CSIRO, and Zebedee Nicholls, The University of Melbourne

Of all the troubling news in the Intergovernmental Panel on Climate Change (IPCC) report out on Monday, one warning will surely generate the most headlines: under all scenarios examined, Earth is likely to reach the crucial 1.5℃ warming limit in the early 2030s.

As the report makes clear, global warming of 1.5℃, and then 2℃, will be exceeded this century unless we make deep cuts to CO₂ and other greenhouse gas emissions in coming decades.

Climate change and its consequences are already being felt. Beyond 1.5℃, the situation is likely to rapidly deteriorate.

We are among the climate scientists who contributed to the latest IPCC report, including on the question of 1.5C℃ warming. Here, we go beyond the headlines to explain how the 1.5℃ rise is measured – and why maintaining the lowest global warming possible is what really matters.

woman carries fan and sack
The IPCC says Earth is likely to get close to, or reach, 1.5℃ warming by the early 2030s. Amr Nabil/AP

‘The most important goal’

Under the 2015 Paris Agreement, nations agreed to hold global warming to well below 2℃, and preferably limit it to 1.5℃, compared to pre-industrial levels.

The first global stocktake of that agreement will be held in 2023, to assess the world’s progress towards achieving its goals. That’s one of the reasons global warming levels are being so keenly watched right now.

The IPCC’s latest findings say 1.5℃ warming will be reached or exceeded in the early 2030s in all emissions scenarios considered – except the highest emissions scenario, for which the crossing could occur even earlier.

But not all hope is lost. In the very low emissions scenario considered in the report – known officially as “SSP1-1.9” – Earth reaches 1.5℃ warming for a few decades, but drops back below it by the end of the century.

This point is important. It’s still possible for Earth to keep below 1.5℃ global warming this century, if we rapidly cut emissions to net-zero. All other scenarios lead to further global warming once 1.5℃ is reached.

However, if maintaining 1.5℃ is not possible, the next goal should be to limit global warming to 1.6℃, then 1.7℃ and so on. Limiting warming to the lowest possible level is the most important goal. Every bit of warming we avoid will reduce the climate risks we face.

Read more: This is the most sobering report card yet on climate change and Earth’s future. Here’s what you need to know

wind turbines
It’s still possible for Earth to keep below 1.5℃ global warming this century, if we cut emissions quickly and deeply. Shutterstock

How 1.5℃ warming is measured

The declaration that Earth has reached 1.5℃ warming since the pre-industrial era will not be made after a single year, or a single location, passes that threshold.

The warming is measured as a global average over 20 years, to account for natural variability in the system.

Before global average temperatures officially reach 1.5℃ warming, we can expect quite a few years will exceed that limit. In fact, global temperatures exceeded 1.5℃ warming during individual months at the peak of the 2015-16 El Niño.

The industrial era – and associated greenhouse gas emissions – started in the 1700s. But there is almost no observed climate data on land outside Europe before the mid-19th century.

So, the period of 1850-1900 is used to approximate pre-industrial conditions. The IPCC estimates there was a likely temperature change of between -0.1 to +0.3℃ for the century or so before this where climate data is lacking.

According to the latest IPCC findings, Earth’s average temperature in the last decade was 1.09℃ warmer than the pre-industrial baseline. Obviously, this goes most of the way to 1.5℃ of warming. The IPCC says this warming is unequivocally the result of human influence.

two men lie in sun
Earth has warmed by 1.09℃ since pre-industrial times. Joel Carrett/AAP

The new science

Several innovations have helped inform the IPCC’s latest assessment. For the first time, the IPCC’s estimate of future global temperature change is based on three factors.

First are projections using new scenarios “Shared Socio-economic Pathways” or SSPs. Each pathway refers to different trajectories the world’s society and economy could take, and the emissions that would result.

A range of climate models – the result of much global scientific effort – is used to simulate climate change in response to each pathway.

Second, climate models are verified against observed climate data. Climate models are essential tools, but should always be used carefully. This grounding in observations was particularly needed with the latest round of climate models, to bring their results in line with other types of evidence.

Read more: Yes, a few climate models give unexpected predictions – but the technology remains a powerful tool

Third, the IPCC used an assessment of “climate sensititivty” – how sensitive Earth’s temperature is to a doubling of global CO₂ concentrations. The IPCC’s assessment of the evidence puts climate sensitivity at likely between 2.5℃ and 4℃, with low-likelihood possibilities of less than 2℃ or more than 5℃.

If humanity is lucky, and actual climate sensitivity is in the lowest plausible range, Earth may not reach the 1.5℃ warming limit under the lowest emissions scenarios (but still will under the medium or high ones). If we are unlucky and climate sensitivity is in the high range, the need to quickly reach net-zero emissions becomes even greater.

The following diagram from the latest IPCC report shows the estimated timeframe for reaching various global warming levels, under different Shared Socio-economic Pathways and climate sensitivity values.


Where does this leave us?

The latest IPCC findings confirm Earth will be in the ballpark of 1.5℃ warming in the early 2030s. What happens after that depends on the decisions we make today.

With deep and sustained reductions in CO₂ and other greenhouse gas emissions in coming decades, we could keep warming around the 1.5℃ mark and then bring it below that threshold by the end of the century.

The IPCC findings are worrying, but should not be a distraction from our global climate efforts. Staying below 1.5℃ warming is important. But maintaining the lowest global warming we can – whether or not we exceed the 1.5℃ goal – is what really matters.

To explore climate change in your region and around the world at 1.5℃ and higher global warming levels, see the IPCC’s Interactive Atlas.




Read more: Climate change has already hit Australia. Unless we act now, a hotter, drier and more dangerous future awaits, IPCC warns

Click here to read more of The Conversation’s coverage of the IPCC reportThe Conversation

Michael Grose, Climate projections scientist, CSIRO; Malte Meinshausen, A/Prof., School of Earth Sciences, The University of Melbourne; Pep Canadell, Chief research scientist, Climate Science Centre, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO, and Zebedee Nicholls, PhD Researcher at the Climate & Energy College, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate change has already hit Australia. Unless we act now, a hotter, drier and more dangerous future awaits, IPCC warns

Michael Grose, CSIRO; Joelle Gergis, Australian National University; Pep Canadell, CSIRO, and Roshanka Ranasinghe

Australia is experiencing widespread, rapid climate change not seen for thousands of years and may warm by 4℃ or more this century, according to a highly anticipated report by the Intergovernmental Panel on Climate Change (IPCC).

The assessment, released on Monday, also warns of unprecedented increases in climate extremes such as bushfires, floods and drought. But it says deep, rapid emissions cuts could spare Australia, and the world, from the most severe warming and associated harms.

The report is the sixth produced by the IPCC since it was founded in 1988 and provides more regional information than any previous version. This gives us a clearer picture of how climate change will play out in Australia specifically.

It confirms the effects of human-caused climate change have well and truly arrived in Australia. This includes in the region of the East Australia Current, where the ocean is warming at a rate more than four times the global average.

We are climate scientists with expertise across historical climate change, climate projections, climate impacts and the carbon budget. We have been part of the international effort to produce the IPCC report over the past three years.

The report finds even under a moderate emissions scenario, the global effects of climate change will worsen significantly over the coming years and decades. Every fraction of a degree of global warming increases the likelihood and severity of many extremes. That means every effort to reduce greenhouse gas emissions matters.

men float furniture through floodwaters
As the climate becomes more extreme, flood risk increases. AAP

Australia is, without question, warming

Australia has warmed by about 1.4℃ since 1910. The IPCC assessment concludes the extent of warming in both Australia and globally are impossible to explain without accounting for the extra greenhouse gases in the atmosphere from human activities.

The report introduces the concept of Climate Impact-Drivers (CIDs): 30 climate averages, extremes and events that create climate impacts. These include heat, cold, drought and flood.

The report confirms global warming is driving a significant increase in the intensity and frequency of extremely hot temperatures in Australia, as well as a decrease in almost all cold extremes. The IPCC noted with high confidence that recent extreme heat events in Australia were made more likely or more severe due to human influence.

These events include:

  • the Australian summer of 2012–13, also known as the Angry Summer, when more than 70% of Australia experienced extreme temperatures
  • the Brisbane heatwave in 2014
  • extreme heat preceding the 2018 Queensland fires
  • the heat leading into the Black Summer bushfires of 2019-20.

The IPCC report notes very high confidence in further warming and heat extremes through the 21st century – the extent of which depends on global efforts to reduce greenhouse gas emissions.

If global average warming is limited to 1.5℃ this century, Australia would warm to between 1.4℃ to 1.8℃. If global average warming reaches 4℃ this century, Australia would warm to between 3.9℃ and 4.8℃ .


The IPCC says as the planet warms, future heatwaves in Australia – and globally – will be hotter and last longer. Conversely, cold extremes will be both less intense and frequent.

Hotter temperatures, combined with reduced rainfall, will make parts of Australia more arid. A drying climate can lead to reduced river flows, drier soils, mass tree deaths, crop damage, bushfires and drought.

The southwest of Western Australia remains a globally notable hotspot for drying attributable to human influence. The IPCC says this drying is projected to continue as emissions rise and the climate warms. In southern and eastern Australia, drying in winter and spring is also likely to continue. This phenomenon is depicted in the graphic below.


Climate extremes on the rise

Heat and drying are not the only climate extremes set to hit Australia in the coming decades. The report also notes:

  • observed and projected increases in Australia’s dangerous fire weather
  • a projected increase in heavy and extreme rainfall in most places in Australia, particularly in the north
  • a projected increase in river flood risk almost everywhere in Australia.

Under a warmer climate, extreme rainfall in a single hour or day can become more intense or more frequent, even in areas where the average rainfall declines.

For the first time, the IPCC report provides regional projections of coastal hazards due to sea level rise, changing coastal storms and coastal erosion – changes highly relevant to beach-loving Australia.

This century, for example, sandy shorelines in places such as eastern Australia are projected to retreat by more than 100 metres, under moderate or high emissions pathways.

homes on sand
Some sandy shorelines may retreat by more than 100 metres. James Gourley/AAP

Hotter, more acidic oceans

The IPCC report says globally, climate change means oceans are becoming more acidic and losing oxygen. Ocean currents are becoming more variable and salinity patterns – the parts of the ocean that are saltiest and less salty – are changing.

It also means sea levels are rising and the oceans are becoming warmer. This is leading to an increase in marine heatwaves such as those which have contributed to mass coral bleaching on the Great Barrier Reef in recent decades.

Notably, the region of the East Australia Current which runs south along the continent’s east coast is warming at a rate more than four times the global average.

The phenomenon is playing out in all regions with so-called “western boundary currents” – fast, narrow ocean currents found in all major ocean gyres. This pronounced warming is affecting marine ecosystems and aquaculture and is projected to continue.

Read more: We just spent two weeks surveying the Great Barrier Reef. What we saw was an utter tragedy

bleached coral with diver
The region of the East Australia Current, which includes the Great Barrier Reef, is warming at a rate more than four times the global average. XL Catlin Seaview Survey

Where to from here?

Like all regions of the world, Australia is already feeling the effects of a changing climate.

The IPCC confirms there is no going back from some changes in the climate system. However, the consequences can be slowed, and some effects stopped, through strong, rapid and sustained reductions in global greenhouse gas emissions.

And now is the time to start adapting to climate change at a large scale, through serious planning and on-ground action.

To find out more about how climate change will affect Australia, the latest IPCC report includes an Interactive Atlas. Use it to explore past trends and future projections for different emissions scenarios, and for the world at different levels of global warming.




Read more: This is the most sobering report card yet on climate change and Earth’s future. Here’s what you need to know

Click here to read more of The Conversation’s coverage of the IPCC reportThe Conversation

Michael Grose, Climate projections scientist, CSIRO; Joelle Gergis, Senior Lecturer in Climate Science, Australian National University; Pep Canadell, Chief research scientist, Climate Science Centre, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO, and Roshanka Ranasinghe, Professor of Climate Change impacts and Coastal Risk

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This is the most sobering report card yet on climate change and Earth’s future. Here’s what you need to know

Pep Canadell, CSIRO; Joelle Gergis, Australian National University; Malte Meinshausen, The University of Melbourne; Mark Hemer, CSIRO, and Michael Grose, CSIRO

Earth has warmed 1.09℃ since pre-industrial times and many changes such as sea-level rise and glacier melt are now virtually irreversible, according to the most sobering report yet by the Intergovernmental Panel on Climate Change (IPCC).

The report also found escape from human-caused climate change is no longer possible. Climate change is now affecting every continent, region and ocean on Earth, and every facet of the weather.

The long-awaited report is the sixth assessment of its kind since the panel was formed in 1988. It will give world leaders the most timely, accurate information about climate change ahead of a crucial international summit in Glasgow, Scotland in November.

The IPCC is the peak climate science body of the United Nations and the World Meteorological Organization. It is the global authority on the state of Earth’s climate and how human activities affect it. We are authors of the latest IPCC report and have drawn from the work of thousands of scientists from around the world to produce this new assessment.

Sadly, there is hardly any good news in the 3,900 pages of text released today. But there is still time to avert the worst damage, if humanity chooses to.

melting glacier
Escape from human-caused climate change is no longer possible. John McConnico/AP

It’s unequivocal: humans are warming the planet

For the first time, the IPCC states unequivocally — leaving absolutely no room for doubt – humans are responsible for the observed warming of the atmosphere, lands and oceans.

The IPCC finds Earth’s global surface temperature warmed 1.09℃ between 1850-1900 and the last decade. This is 0.29℃ warmer than in the previous IPCC report in 2013. (It should be noted that 0.1℃ of the increase is due to data improvements.)

Read more: Monday’s IPCC report is a really big deal for climate change. So what is it? And why should we trust it?

The IPCC recognises the role of natural changes to the Earth’s climate. However, it finds 1.07℃ of the 1.09℃ warming is due to greenhouse gases associated with human activities. In other words, pretty much all global warming is due to humans.

Global surface temperature has warmed faster since 1970 than in any other 50-year period over at least the last 2,000 years, with the warming also reaching ocean depths below 2,000 metres.

The IPCC says human activities have also affected global precipitation (rain and snow). Since 1950, total global precipitation has increased, but while some regions have become wetter, others have become drier.

The frequency and intensity of heavy precipitation events have increased over most land areas. This is because the warmer atmosphere is able to hold more moisture — about 7% more for each additional degree of temperature — which makes wet seasons and rainfall events wetter.

people queue in heavy rain
The frequency and intensity of heavy precipitation events have increased. David Gray/AAP

Higher concentrations of CO₂, growing faster

Present-day global concentrations of atmospheric carbon dioxide (CO₂) are higher and rising faster than at any time in at least the past two million years.

The speed at which atmospheric CO₂ has increased since the industrial revolution (1750) is at least ten times faster than at any other time during the last 800,000 years, and between four and five times faster than during the last 56 million years.

About 85% of CO₂ emissions are from burning fossil fuels. The remaining 15% are generated from land use change, such as deforestation and degradation.

Read more: More livestock, more carbon dioxide, less ice: the world’s climate change progress since 2019 is (mostly) bad news

Concentrations of other greenhouse gases are not doing any better. Both methane and nitrous oxide, the second and third biggest contributors to global warming after CO₂, have also increased more quickly.

Methane emissions from human activities largely come from livestock and the fossil fuel industry. Nitrous oxide emissions largely come from the use of nitrogen fertiliser on crops.

Cows in a misty field
Methane emissions, a more potent greenhouse gas than carbon dioxide, largely come from livestock. Shutterstock

Extreme weather on the rise

Hot extremes, heatwaves and heavy rain have also become more frequent and intense across most land regions since 1950, the IPCC confirms.

The report highlights that some recently observed hot extremes, such as the Australian summer of 2012–2013, would have been extremely unlikely without human influence on the climate.

Human influence has also been detected for the first time in compounded extreme events. For example, incidences of heatwaves, droughts and fire weather happening at the same time are now more frequent. These compound events have been seen in Australia, Southern Europe, Northern Eurasia, parts of the Americas and African tropical forests.

Oceans: hotter, higher and more acidic

Oceans absorb 91% of the energy from the increased atmospheric greenhouse gases. This has led to ocean warming and more marine heatwaves, particularly over the past 15 years.

Marine heatwaves cause the mass death of marine life, such as from coral bleaching events. They also cause algal blooms and shifts in the composition of species. Even if the world restricts warming to 1.5-2℃, as is consistent with the Paris Agreement, marine heatwaves will become four times more frequent by the end of the century.

Read more: Watching a coral reef die as climate change devastates one of the most pristine tropical island areas on Earth

Melting ice sheets and glaciers, along with the expansion of the ocean as it warms, have led to a global mean sea level increase of 0.2 metres between 1901 and 2018. But, importantly, the speed sea level is rising is accelerating: 1.3 millimetres per year during 1901-1971, 1.9mm per year during 1971-2006, and 3.7mm per year during 2006-2018.

Ocean acidification, caused by the uptake of CO₂, has occurred over all oceans and is reaching depths beyond 2,000m in the Southern Ocean and North Atlantic.

For low-lying islands in the Pacific, sea level rise poses an existential threat. Shutterstock

Many changes are already irreversible

The IPCC says if Earth’s climate was stabilised soon, some climate change-induced damage could not be reversed within centuries, or even millennia. For example, global warming of 2℃ this century will lead to average global sea level rise of between two and six metres over 2,000 years, and much more for higher emission scenarios.

Globally, glaciers have been synchronously retreating since 1950 and are projected to continue to melt for decades after the global temperature is stabilised. Meanwhile the acidification of the deep ocean will remain for thousands of years after CO₂ emissions cease.

Read more: We mapped the world’s frozen peatlands – what we found was very worrying

The report does not identify any possible abrupt changes that would lead to an acceleration of global warming during this century – but does not rule out such possibilities.

The prospect of permafrost (frozen soils) in Alaska, Canada, and Russia crossing a tipping point has been widely discussed. The concern is that as frozen ground thaws, large amounts of carbon accumulated over thousands of years from dead plants and animals could be released as they decompose.

The report does not identify any globally significant abrupt change in these regions over this century, based on currently available evidence. However, it projects permafrost areas will release about 66 billion tonnes of CO₂ for each additional degree of warming. These emissions are irreversible during this century under all warming scenarios.

Close-up of frozen soil
Melting permafrost could release 66 billion tonnes of CO₂ into the atmosphere. Shutterstock

How we can stabilise the climate

Earth’s surface temperature will continue to increase until at least 2050 under all emissions scenarios considered in the report. The assessment shows Earth could well exceed the 1.5℃ warming limit by early 2030s.

If we reduce emissions sufficiently, there is only a 50% chance global temperature rise will stay around 1.5℃ (including a temporary overshoot of up to 0.1℃). To get Earth back to below 1.5℃ warming, CO₂ would need to be removed from the atmosphere using negative emissions technologies or nature-based solutions.

Global warming stays below 2℃ during this century only under scenarios where CO₂ emissions reach net-zero around or after 2050.

Read more: We’ve made progress to curb global emissions. But it’s a fraction of what’s needed

The IPCC analysed future climate projections from dozens of climate models, produced by more than 50 modelling centres around the world. It showed global average surface temperature rises between 1-1.8℃ and 3.3-5.7℃ this century above pre-industrial levels for the lowest and highest emission scenarios, respectively. The exact increase the world experiences will depend on how much more greenhouse gases are emitted.

The report states, with high certainty, that to stabilise the climate, CO₂ emissions must reach net zero, and other greenhouse gas emissions must decline significantly.

We also know, for a given temperature target, there’s a finite amount of carbon we can emit before reaching net zero emissions. To have a 50:50 chance of halting warming at around 1.5℃, this quantity is about 500 billion tonnes of CO₂.

At current levels of CO₂ emissions this “carbon budget” would be used up within 12 years. Exhausting the budget will take longer if emissions begin to decline.

The IPCC’s latest findings are alarming. But no physical or environmental impediments exist to hold warming to well below 2℃ and limit it to around 1.5℃ – the globally agreed goals of the Paris Agreement. Humanity, however, must choose to act.




Click here to read more of The Conversation’s coverage of the IPCC reportThe Conversation

Pep Canadell, Chief research scientist, Climate Science Centre, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO; Joelle Gergis, Senior Lecturer in Climate Science, Australian National University; Malte Meinshausen, A/Prof., School of Earth Sciences, The University of Melbourne; Mark Hemer, Principal Research Scientist, Oceans and Atmosphere, CSIRO, and Michael Grose, Climate projections scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Monday’s IPCC report is a really big deal for climate change. So what is it? And why should we trust it?

Chinatopix via AP

David Karoly, CSIROOn Monday, an extremely important report on the physical science of climate change will be released to the world. Produced by the Intergovernmental Panel on Climate Change (IPCC), the report will give world leaders the most up-to-date information about climate change to inform their policies.

It is an enormous undertaking, and has been a long time coming.

This report is the culmination of a marathon five-year assessment, writing, review and approval process from 234 leading scientists hailing from more than 60 countries. These scientists have worked together to rigorously evaluate the world’s climate change research papers — more than 14,000 of them.

I’ve been involved with the IPCC reports in multiple roles since 1997. For this current report, I was a review editor for one chapter.

This IPCC assessment report is the sixth overall, and the first since 2013. A lot has changed since then, from major governments setting ambitious climate targets, to devastating floods, fires and heatwaves across the world.

So what is the IPCC, and why does this report matter so much? And given the report is commissioned and approved by national governments, should we trust it?

What is the IPCC?

The Intergovernmental Panel on Climate Change was first established in 1988 by the United Nations Environment Programme and the World Meteorological Organization. Their aim was to provide policymakers with regular and comprehensive scientific assessments on climate change, at a time when climate change was becoming a more mainstream concern around the world.

These reports assess the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation. They’re required to be policy-relevant yet policy-neutral. They contain findings, and state the confidence with which the finding is made, but do not recommend action.

A protester holding a sign that says 'listen to the science, IPCC report'.
This report is the sixth since the IPCC was established in 1988.

The first assessment was completed in 1990, and found:

emissions resulting from human activities are substantially increasing the concentrations of […] carbon dioxide [and other greenhouse gases]. These increases will enhance the greenhouse effect, resulting on average in an additional warming of the Earth’s surface.

Since then, new assessment cycles have been completed every five to seven years.

The overall assessment — the Sixth Assessment Report — is divided into three main parts. Monday’s report is the first part – on the physical science basis for climate change – and was delayed by almost a year due to COVID restrictions.

The next two parts will be released in 2022. One will cover the impacts, adaptation and vulnerability of, for example, people, ecosystems, agriculture, cities, and more. The other will cover the economics and mitigation of climate change.

The Sixth Assessment Report will culminate in a synthesis report, combining the first three parts, in September 2022.

What will we learn?

The report will provide the most updated and comprehensive understanding of the climate system and climate change, both now and into the future. For that reason, it’s relevant to everyone: individuals, communities, businesses and all levels of government.

Read more:
Climate explained: how the IPCC reaches scientific consensus on climate change

It will tell us how fast carbon dioxide emissions have been rising, and where they’re coming from. It’ll also tell us how global temperatures and rainfall patterns have changed, and how they are expected to change this century, with associated confidence levels.

Compared to the previous report in 2013, this report puts greater emphasis on regional climate change, on changes in extreme events, and how these events are linked to human-caused climate change.

This greater emphasis on extreme events at regional scales makes it even more important to policy makers and the public.

In recent months the world has watched in horror as heatwaves, bushfires and floods toppled homes and buildings, killing hundreds across China, Europe and North America. The report will help put disasters like these in the context of climate change, noting that similar events are expected to be more frequent and severe in a warming world.

The report also examines the effects of different levels of global warming, such as 1.5℃ and 2℃. It also looks at when such warming is likely to be reached.

Read more:
5 things to watch for in the latest IPCC report on climate science

Why should I trust it?

The scope of each IPCC report is prepared by scientists and approved by representatives of all governments. The 234 scientists who wrote the report are selected based on their expertise, and represent as many countries as possible.

The reports go through multiple stages of drafting and review. The first draft of the current report had more than 23,000 review comments from experts. Each comment received an individual response.

The second draft had more than 50,000 review comments from experts and governments, and these guided the preparation of the final draft.

You may be thinking that the IPCC reports should not be trusted because they involve government inputs and approval. However, this is probably one of their strengths. Involving government representatives ensures the reports are relevant to the policy interests of all governments.

Indeed, the multi-stage review and revision process used for the IPCC reports has been used as a model for international assessments of other scientific topics.

Can I read it?

The report will be released and free to read at 6pm Australian Eastern Standard time (10am Paris time) on Monday. But each chapter in the final report will be more than 100 pages long in a small font, so few people will read it all.

The most accessible part of the report is its Summary for Policymakers, aimed at a general readership and drafted by the expert authors.

The approval meeting for this report has been taking place over the last two weeks in Paris, as a video conference meeting of government representatives. The meeting approves each chapter, but most time is spent considering and approving the Summary for Policymakers.

Read more:
Top climate scientist: I put myself through hell as an IPCC convening lead author, but it was worth it

Every line in this summary is considered separately, comments from government representatives are considered, and changes must be approved by consensus of all governments. Sometimes reaching consensus can take a long time.

It’s clear the IPCC brings the best of global science together. It’s vital that governments keep the findings of this report front of mind in their decision-making, if the world is to avoid the worst-case climate scenarios.The Conversation

David Karoly, Chief Research Scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

IPCC cities conference tackles gaps between science and climate action on the ground

File 20180313 131591 3n8dga.jpg?ixlib=rb 1.1
The IPCC’s first cities conference revealed the challenges in bridging the gaps between scientific knowledge and policy practice, and between cities in developed and developing nations.
Cities IPCC/Twitter

Jago Dodson, RMIT University

Some 600 climate scientists, urban researchers, policymakers and practitioners attended the International Panel on Climate Change’s (IPCC) first ever conference on cities last week. Hosted in Edmonton, Canada, it was organised as a forum to share knowledge and advice in support of the sixth IPCC Assessment Report (AR6) due in 2021.

The significance of a UN-organised global scientific conference on climate change and cities should not be underestimated. Urbanisation has been a United Nations concern since 1963. Policy attention strengthened in the 1970s when the UN Habitat agency was established. This focus was redoubled in the mid-2000s when it was reported that more than half of the global population was now urban.

Climate change has been a topic of UN action since 1988, with policy attention intensifying in the late 1990s and mid-2010s. Appreciation has since grown that with 55% of the world’s people now living in cities, this is where where efforts to mitigate and adapt to climate change must be focused.

Read more:
This is why we cannot rely on cities alone to tackle climate change

A collision of science, practice and politics

By venturing onto urban terrain the IPCC faces some interesting scientific questions. To a large degree biological or physical systems can be studied as objective phenomena that behave according to discoverable and predictable patterns. Carbon dioxide objectively traps solar radiation leading to climatic warming; biological species die at temperatures above their tolerance.

By contrast cities are riven with historical, social, economic, cultural and political dynamics. The theoretical and conceptual frames that scientists apply to cities are subject to many biases.

We certainly can calculate the emissions a city produces and chart the likely impacts on it from a changing climate. But the reasons why a city came to emit so much and how it responds to the need to reduce emissions and adapt to impacts are highly contingent. Objective validation and verification are difficult. Identifying causality and forward pathways is very difficult.

There is also a vast divide between the physical and social science of cities and the policymakers and practitioners who shape urban development. Research shows that most urban professionals simply do not read urban science. Instead they draw on practice knowledge acquired from peer practitioners via an array of non-scientific channels and networks.

These difficulties were observable at the IPCC cities conference. It was scientific in purpose but a subtle politics was at play. Rather than being convened by a scientific body, the conference was co-ordinated as an instrument of the world’s national polities and the IPCC, organised by a mix of UN organisations and NGO networks, and sponsored by a local, provincial and national government.

Fewer than two-thirds of delegates were scientists; the remaining 40 per cent were policy officials and practitioners. The problem of connecting scientific and practice knowledge was often on display.

Many cities have accepted the clear scientific evidence on climate change and accompanying global targets. These cities are striving at the local scale to cut emissions and adapt to changing climate patterns. For many, their main need is for knowledge of practical policies and programs, rather than more evidence of climate change impacts or mitigation technologies.

Often these cities are racing far ahead of slow and certain science. They are sharing practical experience of mitigation and adaptation strategies via self-organising peer-city networks. Finding ways to link inventive but unsystematic practice knowledge with the formal peer-reviewed processes of orthodox science will be a critical task for climate change scientists and policymakers.

Read more:
How American cities & states are fighting climate change globally

Policymakers are also grappling with how to implement global agreements within complex international arrangements. There face myriad tiers of national, regional, city and local governance, involving a plethora of discrete public, private and civic actors.

For this group, their priorities at the IPCC cities conference concerned policy processes and institutional design, political commitment and implementation instruments. Their needs are for policy, institutional and political science as much as for further scientific detail on climate change.

What did these encounters reveal?

The conference generated many fascinating insights. One major theme was the question of informality.

Many cities beyond the developed world are weakly governed. Multiple dimensions of urban life, including housing and infrastructure, are organised via informal institutions. Achieving effective action in these circumstances is a considerable policy problem.

A related problem is the gross geographical imbalance in scientific effort and focus on urban climate questions. Most research focuses on the cities of the developed West. And most of those are comparatively well resourced to respond to climate change.

In contrast, the cities of the developing world lack a systematic data and research base to enable effective and timely climate action. Yet these are the cities where many of the most severe climate impacts will be felt. Resolving this inequity is a fundamental international scientific challenge, as is growing the capacity to build a better evidence base.

Another question the IPCC needs to navigate is the boundary between science and politics in urban climate policy. During conference plenaries, the moderator — a former city mayor — excluded questions about specific political representatives’ stances on climate change according to apolitical IPCC rules. Yet questions about the effects on cities of neoliberalism were deemed permissible.

Urban scientists will require an especially nuanced framing of their research agenda if they are to address the very material politics of urban climate policy via theoretical abstraction alone.

Read more:
While nations play politics, cities and states are taking up the climate challenge

The conference also provided some memorable highlights. William Rees, the originator of ecological footprint theory, lambasted delegates for not adequately appreciating the absolute material limits to resource exploitation. And the youth delegates received a standing ovation as the cohort who will be grappling with urban climate effects long after their older peers have departed.

William Rees explains the origins of the ecological footprint.

An agenda for urban climate action

The conference released a research agenda. This outlines the urgent need for inclusive and socially transformative action on climate change, improved evidence and information to support climate responses, and new funding and finance mechanisms to make this possible. It’s a very high-level guide for climate and urban scientists seeking to better understand climate change impacts on cities.

The conference appears to have met the IPCC’s needs to compile and review a large volume of scientific and practice insight for its assessment reporting. Whether it will have a wider effect on climate policy and action in cities remains unclear.

The ConversationThe participating scientists and practitioners certainly shared a general commitment to advancing the urban climate agenda. But it remains uncertain whether methodical scientific processes will be timely enough to meet the accelerating and expanding demands of urgent urban climate action.

Jago Dodson, Professor of Urban Policy and Director, Centre for Urban Research, RMIT University

This article was originally published on The Conversation. Read the original article.