UN climate change report: land clearing and farming contribute a third of the world’s greenhouse gases



Farming emits greenhouse gases, but the land can also store them.
Johny Goerend/Unsplash, CC BY-SA

Mark Howden, Australian National University

We can’t achieve the goals of the Paris Climate Agreement without managing emissions from land use, according to a special report released today by the Intergovernmental Panel on Climate Change (IPCC).

Emissions from land use, largely agriculture, forestry and land clearing, make up some 22% of the world’s greenhouse gas emissions. Counting the entire food chain (including fertiliser, transport, processing, and sale) takes this contribution up to 29%.




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The report, which synthesises information from some 7,000 scientific papers, found there is no way to keep global warming under 2℃ without significant reductions in land sector emissions.

Land puts out emissions – and absorbs them

The land plays a vital role in the carbon cycle, both by absorbing greenhouse gases and by releasing them into the atmosphere. This means our land resources are both part of the climate change problem and potentially part of the solution.

Improving how we manage the land could reduce climate change at the same time as it improves agricultural sustainability, supports biodiversity, and increases food security.

While the food system emits nearly a third of the world’s greenhouse gases – a situation also reflected in Australia – land-based ecosystems absorb the equivalent of about 22% of global greenhouse gas emissions. This happens through natural processes that store carbon in soil and plants, in both farmed lands and managed forests as well as in natural “carbon sinks” such as forests, seagrass and wetlands.




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There are opportunities to reduce the emissions related to land use, especially food production, while at the same time protecting and expanding these greenhouse gas sinks.

But it is also immediately obvious that the land sector cannot achieve these goals by itself. It will require substantial reductions in fossil fuel emissions from our energy, transport, industrial, and infrastructure sectors.

Overburdened land

So, what is the current state of our land resources? Not that great.

The report shows there are unprecedented rates of global land and freshwater used to provide food and other products for the record global population levels and consumption rates.

For example, consumption of food calories per person worldwide has increased by about one-third since 1961, and the average person’s consumption of meat and vegetable oils has more than doubled.

The pressure to increase agricultural production has helped push about a quarter of the Earth’s ice-free land area into various states of degradation via loss of soil, nutrients and vegetation.

Simultaneously, biodiversity has declined globally, largely because of deforestation, cropland expansion and unsustainable land-use intensification. Australia has experienced much the same trends.




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Climate change exacerbates land degradation

Climate change is already having a major impact on the land. Temperatures over land are rising at almost twice the rate of global average temperatures.

Linked to this, the frequency and intensity of extreme events such as heatwaves and flooding rainfall has increased. The global area of drylands in drought has increased by over 40% since 1961.

These and other changes have reduced agricultural productivity in many regions – including Australia. Further climate changes will likely spur soil degradation, loss of vegetation, biodiversity and permafrost, and increases in fire damage and coastal degradation.




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Water will become more scarce, and our food supply will become less stable. Exactly how these risks will evolve will depend on population growth, consumption patterns and also how the global community responds.

Overall, proactive and informed management of our land (for food, water and biodiversity) will become increasingly important.

Stopping land degradation helps everyone

Tackling the interlinked problems of land degradation, climate change adaptation and mitigation, and food security can deliver win-wins for farmers, communities, governments, and ecosystems.

The report provides many examples of on-ground and policy options that could improve the management of agriculture and forests, to enhance production, reduce greenhouse gas emissions, and make these areas more robust to climate change. Leading Australian farmers are already heading down these paths, and we have a lot to teach the world about how to do this.

We may also need to reassess what we demand from the land. Farmed animals are a major contributor to these emissions, so plant-based diets are increasingly being adopted.

Similarly, the report found about 25-30% of food globally is lost or wasted. Reducing this can significantly lower emissions, and ease pressure on agricultural systems.

How do we make this happen?

Many people around the world are doing impressive work in addressing some of these problems. But the solutions they generate are not necessarily widely used or applied comprehensively.

To be successful, coordinated policy packages and land management approaches are pivotal. Inevitably, all solutions are highly location-specific and contextual, and it is vital to bring together local communities and industry, as well as governments at all levels.




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Given the mounting impacts of climate change on food security and land condition, there is no time to lose.


The author acknowledges the contributions to authorship of this article by Clare de Castella, Communications Manager, ANU Climate Change Institute.The Conversation

Mark Howden, Director, Climate Change Institute, Australian National University

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

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A report claims koalas are ‘functionally extinct’ – but what does that mean?



Koalas are facing serious threats in the wild.
Mathias Appel/Flickr

Christine Adams-Hosking, The University of Queensland

Today the Australian Koala Foundation announced they believe “there are no more than 80,000 koalas in Australia”, making the species “functionally extinct”.

While this number is dramatically lower than the most recent academic estimates, there’s no doubt koala numbers in many places are in steep decline.

It’s hard to say exactly how many koalas are still remaining in Queensland, New South Wales, Victoria, South Australia and the Australian Capital Territory, but they are highly vulnerable to threats including deforestation, disease and the effects of climate change.

Once a koala population falls below a critical point it can no longer produce the next generation, leading to extinction.




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What does ‘functionally extinct’ mean?

The term “functionally extinct” can describe a few perilous situations. In one case, it can refer to a species whose population has declined to the point where it can no longer play a significant role in their ecosystem. For example, it has been used to describe dingoes in places where they have become so reduced they have a negligible influence on the species they prey on.

Dingoes are top predators, and therefore can play a significant role in some ecosystems. Our innocuous, leaf-eating koala cannot be considered a top predator.

For millions of years koalas have been a key part of the health of our eucalyptus forests by eating upper leaves, and on the forest floor, their droppings contribute to important nutrient recycling. Their known fossil records date back approximately 30 million years so they may have once been a food source for megafauna carnivores.

Functionally extinct can also describe a population that is no longer viable. For example in Southport, Queensland, native oyster reef beds are functionally extinct because more than 99% of the habitat has been lost and there are no individuals left to reproduce.

Finally, functionally extinct can refer to a small population that, although still breeding, is suffering from inbreeding that can threaten its future viability. We know that at least some koala populations in urban areas are suffering in this way, and genetic studies on the Koala Coast, located 20kms south-east of Brisbane, show that the population is suffering from reduced genetic variation. In South East Queensland, koalas in some areas have experienced catastrophic declines




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We also know that koala populations in some inland regions of Queensland and New South Wales are affected by climate extremes such as severe droughts and heatwaves and have declined by as much as 80%.

Exhaustive multi-disciplinary koala research continues apace in an effort to find ways of protecting wild koala populations and ensuring that they remain viable now and into the future. Habitat loss, population dynamics, genetics, disease, diet and climate change are some key areas being studied.

How many koalas are there?

Koala researchers are often asked “how many koalas are in the wild?” It’s a hard question to answer. Koalas are not stationary, are patchily distributed throughout an extremely wide range encompassing urban and rural areas in four states and one territory, and are usually difficult to see.

To determine whether each population of koalas scattered across eastern Australia is functionally extinct would require a gargantuan effort.

Koalas are a key part of eucalyptus forests’ health.
Dave Hunt/Flickr, CC BY-NC-SA

In 2016, in an attempt to determine population trends for the koala within the four states, a panel of 15 koala experts used a structured, four-step question format to estimate bioregional population sizes of koalas, and changes in those sizes.

The estimated percentage of koala population loss in Queensland, New South Wales, Victoria and South Australia was 53%, 26%, 14% and 3%, respectively. The estimated total number of koalas for Australia was 329,000 (within a range of 144,000–605,000), with an estimated average decline of 24% over the past three generations and the next three generations.

Since May 2012, koalas have been listed as vulnerable in Queensland, New South Wales and the Australian Capital Territory because populations in these regions have declined significantly or are at risk of doing so.

In the southern states of Victoria and South Australia, koala populations vary widely from abundant to low or locally extinct. Although not currently listed as vulnerable, these koalas are also experiencing a range of serious threats, including low genetic diversity.

To date, the present “vulnerable” listing has not achieved any known positive results for koala populations in Queensland and New South Wales. In fact, recent research invariably shows the opposite.




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This is because the key threats to koalas remain, and are mostly increasing. The primary threat is habitat loss. Koala habitat (primarily eucalyptus woodlands and forests) continues to rapidly diminish, and unless it is protected, restored, and expanded, we will indeed see wild koala populations become “functionally extinct”. We know what comes after that.The Conversation

Christine Adams-Hosking, Honorary Research Fellow, The University of Queensland

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

There’s a lot of bad news in the UN Global Environment Outlook, but a sustainable future is still possible



File 20190410 2909 1ru6uth.jpg?ixlib=rb 1.1
It’s not all doom and gloom – pathways to restore the health of our planet do exist.
wonderisland/Shutterstock

Pedro Fidelman, The University of Queensland

The Sixth Global Environment Outlook (GEO-6), the most comprehensive environmental assessment produced by the UN in five years, brought us both good and bad news.

The environment has continued to deteriorate since the first GEO-6 report in 1997, with potentially irreversible impacts if not effectively addressed. But pathways to significant change do exist, and a sustainable future is still possible.

Launched in March at the fourth session of the United Nations Environment Assembly in Nairobi, the 700-page report involved nearly 200 global experts who collaborated over 18 months.




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It covers, in detail, a range of topics, including air, biodiversity, oceans and coasts, land and freshwater, climate change, human health and energy.

And it assessed the state of the global environment, the effectiveness of policy responses, and possible pathways to achieve the environmental goals of the 2030 Agenda for Sustainable Development.

The good news

There is a fair bit of negative information in the GEO-6, which unfortunately reflects the overall state of environmental affairs globally. But it is not all doom and gloom, the GEO-6 has many positive, solution-oriented messages too.

The GEO-6 advises that pathways and approaches to systemic change exist, which must be scaled up quickly to steer the planet towards more sustainable futures.




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The considerable connections between environmental, social and economic policies can inform multiple goals. So policies addressing entire systems – such as food, energy and waste – are more likely to have beneficial impact.

For instance, reducing our use of fossil fuels leads to health benefits by decreasing outdoor air pollution responsible for premature deaths. And efforts to eliminate hunger (such as changes in agriculture production) can help address climate change, biodiversity loss, land degradation and chemical pollution.

With the window for action closing quickly, given the unprecedented rate of global environmental change, the GEO-6 is calling for more ambitious and innovative policy.

We need significant change leading us to decarbonisation, a circular economy, sustainable agriculture and food systems, and better adapting socio-economic systems to climate change.

The bad news

The GEO-6 warns the overall condition of the global environment continues to deteriorate, driven mainly by population growth, urbanisation, economic development, technological change and climate change.

Here’s what we’re dealing with:

  • air pollution currently causes an estimated 6 to 7 million premature deaths annually
  • we might be witnessing the sixth mass species extinction in the planet’s history
  • 8 million tons of plastic enters the ocean every year as a result of mismanagement of domestic waste in coastal areas
  • warming ocean waters are leading to mass mortality of coral reefs across the world’s tropics
  • 29% of all lands are degradation hotspots
  • pathogen-polluted drinking water and inadequate sanitation cause approximately 1.4 million human deaths annually, with many millions more becoming ill.

These and other issues reported in the GEO-6 will lead to ongoing and potentially irreversible impacts if they are not addressed effectively, and immediately.

Typically, environmental policy efforts are based on individual issues, like air pollution, or industry sectors. But this approach doesn’t address the complexity of contemporary environmental problems that require system-oriented efforts at large scales.

Under current policy scenarios, the environmental dimension of the Sustainable Development Goals, as well as other goals like the Paris Agreement, are unlikely to be achieved.

The GEO-6 calls for urgent, inclusive and sustained action by governments, business and society proportionate to the scale and pace of global environmental change.

What it means for Australia

In Australia, positive action is taking place at state and local levels of government, where support for more ambitious emissions targets is generally stronger than at the Australian government level.

And many sectors of society and business are shifting towards more sustainable practices. The booming uptake of rooftop solar and the development of large-scale renewable projects illustrates such a shift.

But when it comes to sustainable development policies at the national level, Australia lags behind most of the developed world, particularly in relation to energy and climate change policy.




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We don’t yet have long-term certainty for support of the uptake of electric cars, the transition to renewables, the adoption of fuel efficiency standards, and limiting emissions from the manufacturing and resources industry.

Effective strategies to curb land clearing remains to be seen, and only recently Australia has incorporated principles of circular economy into the National Waste Policy.

These do not help Australia meet its agreed commitments under the UN 2030 Agenda for Sustainable Development and associated Sustainable Development Goals.

With long-term environmental, socio-economic and political stability at stake, it is time for commitment, leadership and robust policies that can last beyond the three-year electoral cycle.The Conversation

Pedro Fidelman, Senior research fellow, The University of Queensland

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

Australia’s 2018 environmental scorecard: a dreadful year that demands action


Albert Van Dijk, Australian National University

Environmental news is rarely good. But even by those low standards, 2018 was especially bad. That is the main conclusion from Australia’s Environment in 2018, the latest in an annual series of environmental condition reports, released today.

Every year, we analyse vast amounts of measurements from satellites and on-ground stations using algorithms and prediction models on a supercomputer. These volumes of data are turned into regional summary accounts that can be explored on our Australian Environment Explorer website. We interpret these data, along with other information from national and international reports, to assess how our environment is tracking.

A bad year

Whereas 2017 was already quite bad, 2018 saw many indicators dip even further into the red.




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Temperatures went up again, rainfall declined further, and the destruction of vegetation and ecosystems by drought, fire and land clearing continued. Soil moisture, rivers and wetlands all declined, and vegetation growth was poor.

In short, our environment took a beating in 2018, and that was even before the oppressive heatwaves, bushfires and Darling River fish kills of January 2019.

Indicators of Australia’s environment in 2018 compared with the previous year. Similar to national economic indicators, they provide a summary but also hide regional variations, complex interactions and long-term context.
source: http://www.ausenv.online/2018

The combined pressures from habitat destruction, climate change, and invasive pests and diseases are taking their toll on our unique plants and animals. Another 54 species were added to the official list of threatened species, which now stands at 1,775. That is 47% more than 18 years ago and puts Australia among the world’s worst performers in biodiversity protection. On the upside, the number of predator-proof islands or fenced-off reserves in Australia reached 188 in 2018, covering close to 2,500 square kilometres. They offer good prospects of saving at least 13 mammal species from extinction.

Globally, the increase of greenhouse gases in the atmosphere accelerated again after slowing down in 2017. Global air and ocean temperatures remained high, sea levels increased further, and even the ozone hole grew again, after shrinking during the previous two years.

Sea surface temperatures around Australia did not increase in 2018, but they nevertheless were well above long-term averages. Surveys of the Great Barrier Reef showed further declining health across the entire reef. An exceptional heatwave in late 2018 in Far North Queensland raised fears for yet another bout of coral bleaching, but this was averted when sudden massive downpours cooled surface waters.

The hot conditions did cause much damage to wildlife and vegetation, however, with spectacled flying foxes dropping dead from trees and fire ravaging what was once a tropical rainforest.

While previous environmental scorecards showed a mixed bag of regional impacts, 2018 was a poor year in all states and territories. Particularly badly hit was New South Wales, where after a second year of very poor rainfall, ecosystems and communities reached crisis point. Least affected was southern Western Australia, which enjoyed relatively cool and wet conditions.

Environmental Condition Score in 2018 by state and territory, based on a combination of seven indicators. The large number is the score for 2017, the smaller number the change from the previous year.
source: http://www.ausenv.online/2018

It was a poor year for nature and farmers alike, with growing conditions in grazing, irrigated agriculture and dryland cropping each declining by 17-20% at a national scale. The only upside was improved cropping conditions in WA, which mitigated the 34% decline elsewhere.

A bad start to 2019

Although it is too early for a full picture, the first months of 2019 continued as badly as 2018 ended. The 2018-19 summer broke heat records across the country by large margins, bushfires raged through Tasmania’s forests, and a sudden turn in the hot weather killed scores of fish in the Darling River. The monsoon in northern Australia did not come until late January, the latest in decades, but then dumped a huge amount of rain on northern Queensland, flooding vast swathes of land.




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It would be comforting to believe that our environment merely waxes and wanes with rainfall, and is resilient to yearly variations. To some extent, this is true. The current year may still turn wet and improve conditions, although a developing El Niño makes this less likely.

However, while we are good at acknowledging rapid changes, we are terrible at recognising slow, long-term ones. Underlying the yearly variations in weather is an unmistakable pattern of environmental decline that threatens our future.

What can we do about it?

Global warming is already with us, and strong action is required to avoid an even more dire future of rolling heatwaves and year-round bushfires. But while global climate change requires global action, there is a lot we can and have to do ourselves.




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Australia is one of the world’s most wasteful societies, and there are many opportunities to clean up our act. Achieving progress is not hard, and despite shrill protests from vested interests and the ideologically blind, taking action will not take away our prosperity. Home solar systems and more efficient transport can in fact save money. Our country has huge opportunities for renewable energy, which can potentially create thousands of jobs. Together, we can indeed reduce emissions “in a canter” – all it takes is some clear national leadership.

The ongoing destruction of natural vegetation is as damaging as it is unnecessary, and stopping it will bring a raft of benefits. Our rivers and wetlands are more than just a source of cheap irrigation for big businesses. With more effort, we can save many species from extinction. Our farmers play a vital role in caring for our country, and we need to support them better in doing so.




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Our environment is our life support. It provides us our place to live, our food, health, livelihoods, culture and identity. To protect it is to protect ourselves.


This article was coauthored by Shoshana Rapley, an ANU honours student and research assistant in the Fenner School of Environment and Society.The Conversation

Albert Van Dijk, Professor, Water and Landscape Dynamics, Fenner School of Environment & Society, Australian National University

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

Murray-Darling report shows public authorities must take climate change risk seriously


Arjuna Dibley, Stanford University

The tragic recent events on the Darling River, and the political and policy furore around them, have again highlighted the severe financial and environmental consequences of mismanaging climate risks. The Murray-Darling Royal Commission demonstrates how closely boards of public sector corporate bodies can be scrutinised for their management of these risks.

Public authorities must follow private companies and factor climate risk into their board decision-making. Royal Commissioner Brett Walker has delivered a damning indictment of the Murray Darling Basin Authority’s management of climate-related risks. His report argues that the authority’s senior management and board were “negligent” and fell short of acting with “reasonable care, skill and diligence”. For its part, the authority “rejects the assertion” that it “acted improperly or unlawfully in any way”.

The Royal Commission has also drawn attention to the potentially significant legal and reputational consequences for directors and organisations whose climate risk management is deemed to have fallen short of a rising bar.




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It’s the public sector’s turn

Until recently, scrutiny of how effectively large and influential organisations are responding to climate risks has focused mostly on the private sector.

In Australia it is widely acknowledged among legal experts that private company directors’ duty of “due care and diligence” requires them to consider foreseeable climate risks that intersect with the interests of the company. Indeed, Australia’s companies regulator, ASIC, has called for directors to take a “probative and proactive” approach to these risks.

The recent focus on management of the Murray-Darling Basin again highlights the crucial role public sector corporations (or “public authorities” as we call them) also play in our overall responses to climate change – and the consequences when things go wrong.

Australia’s economy, once dominated by publicly owned enterprises, was reshaped by waves of privatisations in the late 20th century. However, hundreds of public authorities continue to play an important role in our economy. They build and maintain infrastructure, generate energy, oversee superannuation portfolios, provide insurance and manage water resources, among many other activities.

This means that, like their counterparts in the private sector, many face risks associated with climate change. Take Melbourne Water, for instance, a statutory water corporation established to manage the city’s water supply. It will have to contend with increasingly hot summers and reduced rainfall (a physical risk), and also with the risk that government policy in the future might impose stricter conditions on how water is used (a transition risk).

What duties do public authorities owe?

Our new research from the Centre for Policy Development, shows that, at the Commonwealth and Victorian level (and likely in other Australian jurisdictions), the main laws governing officials in public authorities are likely to create similar obligations to those imposed on private company directors.

For instance, a 2013 federal act requires public authority board members to carry out their duties with the degree of “due care and diligence” that a reasonable person would exercise if they were a Commonwealth official in that board position.

The concept of a “reasonable person” is crucial. There is ever-increasing certainty about the human contribution to climate change. New tools and models have been created to measure the impact of climate change on the economy. Climate risks are therefore reasonably foreseeable if you are acting carefully and diligently, and thus public authority directors should consider these risks.

The obligations of public authority directors may, in some cases, go beyond what is required of private company directors. The same act mentioned above requires Commonwealth officials to promote best practice in the way they carry out their duties. While there is still wide divergence in how private companies manage climate change, best practice in leading corporations is moving towards more systematic analysis and disclosure of these risks. Accordingly, a “best practice” obligation places an even higher onus on public sector directors to manage climate risk.

The specific legislation that governs certain public authorities may introduce different and more onerous requirements. For instance, the Murray-Darling Basin Authority’s governing legislation, the Water Act 2007, imposes a number of additional conditions on the authority. This includes the extent to which the minister can influence board decision-making.

Nonetheless, our laws set out a widely applicable standard for public authority directors.

Approaches to better manage public authority climate risks

While some public authorities are already carefully considering how physical and transition climate risks affect their work, our research suggests that standards vary widely.

As with the private sector, a combination of clear expectations for better climate risk management, greater scrutiny and more investment in climate-related capabilities and risk-management frameworks can all play a role in raising the bar. Our research highlights four steps that governments should consider:

  • creating a whole-of-government toolkit and implementation strategy for training and supporting directors to account for climate-risk in decision-making

  • using existing public authority accountability mechanisms – such as the public sector commissioner or auditor general’s office – to more closely scrutinise the management of climate-related financial risks

  • issuing formal ministerial statements of expectations to clarify how public authorities and their directors should manage climate-related risks and policy priorities

  • making legislative or regulatory changes to ensure consistent consideration, management and disclosure of climate risk by public sector decision-makers.




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Measures such as these would set clear expectations for more consistent, sophisticated responses to climate risks by public authorities. However, even without any changes, it should be clear that public authority directors have legal duties to consider climate risks – and that these duties must be taken seriously even when doing so is complicated, controversial or politically sensitive.The Conversation

Arjuna Dibley, Graduate Fellow, Steyer-Taylor Center for Energy Policy and Finance, Stanford University

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

State of the Climate 2018: Bureau of Meteorology and CSIRO


Michael Grose, CSIRO and Lynette Bettio, Australian Bureau of Meteorology

The Australian Bureau of Meteorology and CSIRO have released their fifth biennial State of the Climate report.


State of the Climate 2018 is the latest biennial snapshot of climate change in Australia. It focuses on observed long-term trends that are happening now and are likely to continue into the near future, as well as significant climate events that have occurred over the past two years. These changes are described through the latest observations from CSIRO and Bureau of Meteorology marine, atmospheric and terrestrial monitoring programs.

The report also summarises the latest climate research from Australia and around the world. This will help inform a range of economic, environmental and social risk assessments and responses by government, industry and communities.




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Multiple lines of evidence show the climate system changing in ways that are discernible from natural variability, and consistent with a human influence on climate. These changes are having an impact on our natural and built environment.

In particular, climate change is being felt through an increase in the frequency and severity of high-impact weather events such as heatwaves, extreme fire weather conditions, coastal inundation and marine heatwaves. These trends are projected to continue.

Some of the report’s major findings are described below.

Passing major milestones

Australia’s average air temperature has warmed by just over 1℃ since national records began in 1910. Oceans around Australia have also warmed by around 1℃ since 1910.

Annual mean temperature over Australia and the seas surrounding Australia.
Bureau of Meteorology, Author provided

Atmospheric concentrations of carbon dioxide are rising globally. Emissions from the burning of fossil fuels continue to increase, and are the main contributor to the rise in CO₂, with some contribution from changes in land use.

Atmospheric CO₂ concentrations measured at Cape Grim, Tasmania (one of three main global measuring stations, alongside Mauna Loa, Hawaii, and Nunavut, Canada), have persisted at levels above 400 parts per million (ppm) since 2016. What’s more, the combined concentration of all greenhouse gases exceeded the equivalent of 500 ppm CO₂ in mid-2018. These milestones haven’t been crossed for at least 800,000 years, and likely 2 million years.

Changes in the atmosphere and land

Australia’s warming trend has led to an increase in the frequency of extreme heat events. For example, very high monthly maximum temperatures that used to occur around 2% of the time (based on the average for 1951–80) now happen about 12% of the time (2003–17).

Other elements of Australia’s climate have also shown long-term changes. New analysis techniques now provide a more detailed picture of changes to fire weather through time. The annual total of daily values of the Forest Fire Danger Index is increasing over large areas of Australia. Most regions also saw an increase in the most extreme 10% of fire weather days, and fire seasons have lengthened.

Rainfall in April–October has been steadily decreasing in Western Australia’s Southwest, and has decreased since the 1990s in southeast Australia. In contrast, rainfall has increased in parts of northern Australia since the 1970s.

The observed long-term reduction in rainfall across southern Australia has led to even greater reductions in streamflow. Long-term average streamflow has decreased in most regions of southern Australia, and increased in regions of northern Australia.

A warmer atmosphere can hold more moisture, and this is an important driver of the observed increase in the intensity of short-duration rainfall, sometimes linked to flash flooding. Southern Australia is projected to experience decreases in average rainfall and more time spent in drought. Meanwhile, most of the country can expect an increase in rainfall intensity.

Historically, significant weather and climate events are often the result of the combined influence of several extreme factors at once. Higher temperatures during periods of below-average rainfall, for instance, can exacerbate drought conditions. Temperature, dryness and wind come together to create dangerous bushfire conditions.

Trend in the annual sum of Forest Fire Danger Index, 1978–2017.
Bureau of Meteorology, Author provided

Changes in the ocean

The warming in Australia’s oceans has contributed to longer and more frequent marine heatwaves – defined as periods when sea surface temperatures are much warmer than average. The world’s oceans are a crucial moderator of the climate, taking up more than 90% of the extra heat in the system – most of it is absorbed by the Southern Ocean.

Sea levels continue to rise through the combined effects of warming oceans and melting ice from land-based glaciers and ice sheets. Global average sea level has risen by more than 20cm since 1880, but the rate varies from place to place. About 25% of the CO₂ emitted by human activity diffuses into the oceans, making them more acidic in the process.

The past two years, 2016 and 2017, have seen back-to-back bleaching events in parts of the Great Barrier Reef, linked to marine heatwave events. These changes are very likely linked to warming oceans, and primarily driven by the human influence on the climate.

Global sea level change from 1880 estimated from tide gauges and satellites.
CSIRO, Author provided

Well-established scientific theory and climate model studies both show that the warming would largely not have occurred without the increase in greenhouse gas concentrations. In addition, the current increase in temperatures accords with projections made nearly 30 years ago. Warming is projected to continue into the future as the effect of past emissions continue, and more greenhouse gases are emitted. Australia is projected to experience increases in sea and air temperatures, with more hot days and marine heatwaves, and fewer cool extremes.

It takes time for the climate system to warm in response to increases in greenhouse gases, and the historical emissions over the past century have locked in some warming over the next two decades, regardless of any changes we might make to global emissions in that period. However, by the mid-21st century, higher ongoing emissions of greenhouse gases will lead to greater warming and associated impacts, and reducing emissions will lead to less warming and fewer associated impacts.

Australian average annual temperature 1861-1900 period in observations and global climate models.
CSIRO, Author provided

State of the Climate 2018 can be read on either the Bureau of Meteorology or CSIRO websites. The online report includes an extensive list of references and useful links.

You can also watch accompanying behind-the-scenes videos on our research on climate extremes and ocean warming.The Conversation

Michael Grose, Climate Projections Scientist, CSIRO and Lynette Bettio, , Australian Bureau of Meteorology

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

New UN report outlines ‘urgent, transformational’ change needed to hold global warming to 1.5°C



File 20181008 72124 1ce1rz1.jpg?ixlib=rb 1.1

National Renewable Energy Lab/Flickr, CC BY-NC

Mark Howden, Australian National University and Rebecca Colvin, Australian National University

A landmark report from the Intergovernmental Panel on Climate Change, commissioned at the breakthrough 2015 summit that brokered the Paris climate agreement, outlines what’s at stake in the world’s bid to limit global temperature rise to 1.5℃.

The report, released today, sets out the key practical differences between the Paris agreement’s two contrasting goals: to limit the increase of human-induced global warming to well below 2℃, and to “pursue efforts” to limit warming to 1.5℃.




Read more:
The UN’s 1.5°C special climate report at a glance


Two and a half years in the making, the report provides vital information about whether the Paris Agreement’s more ambitious goal is indeed achievable, what the future may look like under it, and the risks and rewards of hitting the target.

Here are five key questions to which the report provides answers.

Can we limit warming to 1.5℃?

There is no clear yes or no answer to this question.

Put simply, it is not impossible that global warming could be limited to 1.5℃. But achieving this will be profoundly challenging.

If we are to limit warming to 1.5℃, we must reduce carbon dioxide emissions by 45% by 2030, reaching near-zero by around 2050.

Whether we are successful primarily depends on the rate at which government and non-state bodies take action to reduce emissions. Yet despite the urgency, current national pledges under the Paris Agreement are not enough to remain within a 3℃ temperature limit, let alone 1.5℃.

Source: Australian Academy of Science.

Global warming is not just a problem for the future. The impacts are already being felt around the world, with declines in crop yields, biodiversity, coral reefs, and Arctic sea ice, and increases in heatwaves and heavy rainfall. Sea levels have risen by 40.5mm in the past decade and are predicted to continue rising for decades, even if all greenhouse emissions were reduced to zero immediately. Climate adaptation is already needed and will be increasingly so at 1.5℃ and 2℃ of warming.

Rapid action is essential and the next ten years will be crucial. In 2017, global warming breached 1℃. If the planet continues to warm at the current rate of 0.2℃ per decade, we will reach 1.5℃ of warming around 2040. At current emissions rates, within the next 10 to 14 years there is a 2/3 chance we will have used up our entire carbon budget for keeping to 1.5.

How can we limit warming to 1.5℃?

The report says “transformational” change will be needed to limit warming to 1.5℃. Business as usual will not get us there.

Global emissions of carbon dioxide, methane and other greenhouse gases need to reach net zero globally by around 2050. Most economists say putting a price on emissions is the most efficient way to do this.

By 2050, 70-85% of electricity globally will need to be supplied by renewables. Investment in low-carbon and energy-efficient technologies will need to double, whereas investment in fossil-fuel extraction will need to decrease by around a quarter.

Sustainable agriculture is a big piece of the low-carbon puzzle.
CIFOR/Flickr, CC BY-NC

Carbon dioxide removal technology will also be needed to remove greenhouse gases from the atmosphere. But the IPCC’s report warns that relying too heavily on this technology would be a major risk as it has not been used on such a large scale before. Carbon dioxide removal is an extra step that may be needed to keep warming to 1.5℃, not an excuse to keep emitting greenhouse gases.

Production, consumption and lifestyle choices also play a role. Reducing energy demand and food waste, improving the efficiency of food production, and choosing foods and goods with lower emissions and land use requirements will contribute significantly.

Taking such action as soon as possible will be hugely beneficial. The earlier we start, the more time we have to reach net zero emissions. Acting early will mean a smoother transition and less net cost overall. Delay will lead to more haste, higher costs, and a harder landing.

Reducing emissions quickly will also ensure warming is capped as soon as possible, reducing the number and severity of impacts.

Yet severe impacts will still be experienced even if warming is successfully capped at 1.5℃.

What is the cost of 1.5℃ of warming?

Although the Paris Agreement aims to hold global warming as close to 1.5℃ as possible, that doesn’t mean it is a “safe” level. Communities and ecosystems around the world have already suffered significant impacts from the 1℃ of warming so far, and the effects at 1.5℃ will be harsher still.

Poverty and disadvantages will increase as temperatures rise to 1.5℃. Small island states, deltas and low-lying coasts are particularly vulnerable, with increased risk of flooding, and threats to freshwater supplies, infrastructure, and livelihoods.

Warming to 1.5℃ also poses a risk to global economic growth, with the tropics and southern subtropics potentially being hit hardest. Extreme weather events such as floods, heatwaves, and droughts will become more frequent, severe, and widespread, with attendant costs in terms of health care, infrastructure, and disaster response.

The oceans will also suffer in a 1.5℃ warmer world. Ocean warming and acidification are expected to impact fisheries and aquaculture, as well as many marine species and ecosystems.

Coral reefs around the world are seeing increased rates of bleaching.
OIST/Flickr, CC BY

Up to 90% of warm water coral reefs are predicted to disappear when global warming reaches 1.5℃. That would be a dire situation, but far less serious than at 2℃, when the destruction of coral reefs would be almost total (greater than 99% destruction).

How do 1.5℃ and 2℃ compare?

Impacts on both human and natural systems would be very different at 1.5℃ rather than 2℃ of warming. For example, limiting warming to 1.5℃ would roughly halve the number of people globally who are expected to suffer from water scarcity.

Seas would rise by an extra 10cm this century at 2℃ compared with 1.5℃. This means limiting global warming to 1.5℃ would save up to 10.4 million people from the impacts of rising seas.

At 1.5℃ rather than 2℃:

  • up to 427 million fewer people will suffer food and water insecurity, climate risks, and adverse health impacts

  • extreme weather events, heat-related death and disease, desertification, and wildlife extinctions will all be reduced

  • it will be significantly easier to achieve many of the United Nations’ Sustainable Development Goals, including those linked to hunger, poverty, water and sanitation, health, and cities and ecosystems.

How does the 1.5℃ target fit with the Sustainable Development Goals?

The Sustainable Development Goals aim for a world in which people can be healthy, financially stable, well fed, have clean air and water, and live in a secure and pleasant environment. Much of this is consistent with the goal of capping global warming at 1.5℃, which is why the IPCC notes there are synergies if the SDG initiatives and climate action should be explicitly linked.

But some climate strategies may make it harder to achieve particular SDGs. Countries that are highly dependent on fossil fuels for employment and revenue may suffer economically in the transition towards low-carbon energy.

Carefully managing this transition by simultaneously focusing on reducing poverty and promoting equity in decision-making may help avoid the worst effects of such trade-offs. What works in one place may not work in another, so strategies should always be locally appropriate.

Where next?

Limiting global warming to 1.5℃ will require a social transformation, as the world takes rapid action to reduce greenhouse gases. The effects of climate change will continue to shape the world we live in, but there is no doubt we will be far better off under 1.5℃ than 2℃ of global warming.




Read more:
Why is climate change’s 2 degrees Celsius of warming limit so important?


The choices we make today are shaping the future for coming generations. As the new report makes clear, if we are serious about the 1.5℃ target, we need to act now.


The authors gratefully acknowledge the substantial contribution to authorship of this article by of Lamis Kazak, an Australian National University Bachelor of Interdisciplinary Studies (Sustainability) student, as part of a Science Communication Internship with the Climate Change Institute.The Conversation

Mark Howden, Director, Climate Change Institute, Australian National University and Rebecca Colvin, Knowledge Exchange Specialist, Climate Change Institute, Australian National University

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