Scientists hate to say ‘I told you so’. But Australia, you were warned



Without a radical change of course on climate change, Australians will struggle to survive on this continent, let alone thrive.
AAP/Dave Hunt

Will Steffen, Australian National University

Those who say “I told you so” are rarely welcomed, yet I am going to say it here. Australian scientists warned the country could face a climate change-driven bushfire crisis by 2020. It arrived on schedule.

For several decades, the world’s scientific community has periodically assessed climate science, including the risks of a rapidly changing climate. Australian scientists have made, and continue to make, significant contributions to this global effort.

I am an Earth System scientist, and for 30 years have studied how humans are changing the way our planet functions.




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Scientists have, clearly and respectfully, warned about the risks to Australia of a rapidly heating climate – more extreme heat, changes to rainfall patterns, rising seas, increased coastal flooding and more dangerous bushfire conditions. We have also warned about the consequences of these changes for our health and well-being, our society and economy, our natural ecosystems and our unique wildlife.

Today, I will join Dr Tom Beer and Professor David Bowman to warn that Australia’s bushfire conditions will become more severe. We call on Australians,
particularly our leaders, to heed the science.

Prime Minister Scott Morrison comforting a man evacuated from his home during then recent bushfires.
Darren Pateman/AAP

The more we learn, the worse it gets

Many of our scientific warnings over the decades have, regrettably, become reality. About half of the corals on the Great Barrier Reef have been killed by underwater heatwaves. Townsville was last year decimated by massive floods. The southeast agricultural zone has been crippled by intense drought. The residents of western Sydney have sweltered through record-breaking heat. The list could go on.

All these impacts have occurred under a rise of about 1℃ in global average temperature. Yet the world is on a pathway towards 3℃ of heating, bringing a future that is almost unimaginable.

How serious might future risks actually be? Two critical developments are emerging from the most recent science.

First, we have previously underestimated the immediacy and seriousness of many risks. The most recent assessments of the Intergovernmental Panel on Climate Change show that as science progresses, more damaging impacts are projected to occur at lower increases in temperature. That is, the more we learn about climate change, the riskier it looks.




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For Australia, a 3℃ world would likely lead to much harsher fire weather than today, more severe droughts and more intense rainfall events, more prolonged and intense heatwaves, accelerating sea-level rise and coastal flooding, the destruction of the Great Barrier Reef and a large increase in species extinctions and ecosystem degradation. This would be a tough continent to survive on, let alone thrive on.

The city I live in, Canberra, experienced an average seven days per year over 35℃ through the 1981-2010 period. Climate models projected that this extreme heat would more than double to 15 days per year by 2030. Yet in 2019 Canberra experienced 33 days of temperatures over 35℃.

Second, we are learning more about ‘tipping points’, features of the climate system that appear stable but could fundamentally change, often irreversibly, with just a little further human pressure. Think of a kayak: tip it a little bit and it is still stable and remains upright. But tip it just a little more, past a threshold, and you end up underwater.

Features of the climate system likely to have tipping points include Arctic sea ice, the Greenland ice sheet, coral reefs, the Amazon rainforest, Siberian permafrost and Atlantic Ocean circulation.

Dogs hauling a sled through meltwater on coastal sea ice during an expedition in northwest Greenland in June last year.
STEFFEN M. OLSEN/DANISH METEOROLOGICAL INSTITUTE

Heading towards ‘Hothouse Earth’?

These tipping points do not act independently of one another. Like a row of dominoes, tipping one could help trigger another, and so on to form a tipping cascade. The ultimate risk is that such a cascade could take the climate system out of human control. The system could move to a “Hothouse Earth” state, irrespective of human actions to stop it.

Hothouse Earth temperatures would be much higher than in the pre-industrial era – perhaps 5–6℃ higher. A Hothouse Earth climate is likely to be uncontrollable and very dangerous, posing severe risks to human health, economies and political stability, especially for the most vulnerable countries. Indeed, Hothouse Earth could threaten the habitability of much of the planet for humans.

Tipping cascades have happened in Earth’s history. And the risk that we could trigger a new cascade is increasing: a recent assessment showed many tipping elements, including the ones listed above, are now moving towards their thresholds.

Beachgoers swim as smoke haze from bushfires blanketed Sydney last month.
Steven Saphore/AAP

It’s time to listen

Now is the perfect time to reflect on what science-based risk assessments and warnings such as these really mean.

Two or three decades ago, the spectre of massive, violent bushfires burning uncontrollably along thousands of kilometres of eastern Australia seemed like the stuff of science fiction.




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Now we are faced with more than 10 million hectares of bush burnt (and still burning), 29 people killed, more than 2,000 properties and several villages destroyed, and more than one billion animals sent to a screaming, painful death.

Scientists are warning that the world could face far worse conditions in the coming decades and beyond, if greenhouse gas emissions don’t start a sharp downward trend now.

Perhaps, Australia, it’s time to listen.The Conversation

Will Steffen, Emeritus Professor, Australian National University

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

11,000 scientists warn: climate change isn’t just about temperature



Land clearing, cattle populations and carbon emissions stand alongside temperature as important measures of climate change.
DAN PELED/AAP

Thomas Newsome, University of Sydney and William Ripple, Oregon State University

Exactly 40 years ago, a small group of scientists met at the world’s first climate conference in Geneva. They raised the alarm about unnerving climate trends.

Today, more than 11,000 scientists have co-signed a letter in the journal BioScience, calling for urgently necessary action on climate.

This is the largest number of scientists to explicitly support a publication calling for climate action. They come from many different fields, reflecting the harm our changing climate is doing to every part of the natural world.




Read more:
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Why no change?

If you’re thinking not much has changed in the past 40 years, you might be right. Globally, greenhouse gas emissions are still rising, with increasingly damaging effects.

Much of the focus to date has been on tracking global surface temperatures. This makes sense, as goals like “prevent 2℃ of warming” create a relatively simple and easy-to-communicate message.

However, there’s more to climate change than global temperature.

In our paper, we track a broader set of indicators to convey the effects of human activities on greenhouse gas emissions, and the consequent impacts on climate, our environment, and society.

The indicators include human population growth, tree cover loss, fertility rates, fossil fuel subsidies, glacier thickness, and frequency of extreme weather events. All are linked to climate change.

Troubling signs over the past 40 years

Profoundly troubling signs linked to human activities include sustained increases in human and ruminant populations, global tree cover loss, fossil fuel consumption, number of plane passengers, and carbon dioxide emissions.

The concurrent trends on the actual impacts of climate change are equally troubling. Sea ice is rapidly disappearing, and ocean heat, ocean acidity, sea level, and extreme weather events are all trending upwards.

These trends need to be closely monitored to assess how we are responding to the climate emergency. Any one of them could hit a point of no return, creating a catastrophic feedback loop that could make more regions of Earth uninhabitable.




Read more:
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The need for better reporting

We urge national governments to report on how their own results are trending. Our indicators will allow policymakers and the public to better understand the magnitude of this crisis, track progress, and realign priorities to alleviate climate change.

Some of the indicators could even be presented monthly to the public during news broadcasts, as they are arguably more important than the trends in the stock exchange.

It’s not too late to act

In our paper we suggest six critical and interrelated steps that governments, and the rest of humanity, can take to lessen the worst effects of climate change:

  1. prioritise energy efficiency, and replace fossil fuels with low-carbon renewable energy sources,

  2. reduce emissions of short-lived pollutants like methane and soot,

  3. protect and restore the Earth’s ecosystems by curbing land clearing,

  4. reduce our meat consumption,

  5. move away from unsustainable ideas of ever-increasing economic and resource consumption, and

  6. stabilise and ideally, gradually reduce human populations while improving human well-being.

We recognise that many of these recommendations are not new. But mitigating and adapting to climate change will entail major transformations across all six areas.

How can you help?

Individuals can make a difference by reducing meat consumption, voting for political parties and members of government bodies who have clear climate change policies, rejecting fossil fuels where possible, using renewable and clean sources of energy, reducing car and air travel, and joining citizen movements.

Lots of small changes will help inspire larger scale shifts in policy and economic frameworks.

We are encouraged by a recent global surge of concern. Some governments are declaring climate emergencies. Grassroots citizen movements are demanding change.




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As scientists, we urge widespread use of our indicators to track how changes across the six areas above will start to change our ecosystem trajectories.The Conversation

Thomas Newsome, Lecturer, University of Sydney and William Ripple, Distinguished Professor and Director, Trophic Cascades Program, Oregon State University

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

A warning for wine-lovers: climate change is messing with your favourite tipple’s timing



File 20190313 86707 1fmr5a6.jpg?ixlib=rb 1.1
Record-breaking maximum temperatures are changing ripening times in Australia’s wine regions.
Shutterstock

Christopher Davies, CSIRO and Christine Bottcher, CSIRO

While the much-derided “latte set” are stereotyped as the biggest worriers about climate change, it’s the chardonnay crowd who are acutely feeling its effects.

Australia’s wine industry is both world-renowned and economically significant, with around A$5.6 billion in sales in 2016–17, and winemaking and associated tourism responsible for more than 170,000 full and part-time jobs. Statistics also show that wine consumption is now accepted as being just as dinky-di as beer drinking for the average Australian.




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However, record-breaking daily maximum temperatures, warmer than average overnight temperatures, and increasingly erratic weather patterns are playing havoc with the way wine grapes grow and ripen. This has knock-on effects for Australian grape growers, wine producers and consumers.

Climate in the vineyard hits the cellar and the store shelf

Most of Australia’s wine regions have experienced rising average daily temperatures. One effect is changes to ripening times, which has compressed the harvesting season and given wine-makers a crucial logistical headache.

Traditionally, white grape varieties would generally reach optimum ripeness before red ones. While all grapes tend to ripen faster as temperatures rise, this effect is more pronounced for later-ripening varieties (for example Shiraz and Cabernet Sauvignon) than earlier ripening varieties (for example Chardonnay and Riesling).

Australian winegrape varieties are becoming ready for harvest simultaneously.
Shutterstock

The old process of staggered harvesting times for red and white grape varieties was efficient, allowing the winery’s capacity to be used in sequence for different varieties. Now that different varieties are ripening at the same time, vineyards and wineries will have to make tough choices about which grapes to prioritise, and which ones to leave until later, resulting in inferior wine. Alternatively, they could take the expensive decision to increase production capacity by investing in more infrastructure such as fermenters and stainless steel tanks.




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Perhaps you’re thinking that you, the savvy wine drinker, are unaffected by the difficulties faced by winemakers in the vineyards and wineries far away. Unfortunately this isn’t so. Harvesting grapes when they are not at optimal ripeness to solve the logistical problems of processing can lead to lower-value wine.

The fact is that this new reality is costing everyone – grape-growers, winemakers and consumers alike.

And just in case you think that the simple answer is changing Australia’s cultured palates back to beer, think again. Hop production is being hit just as hard by climate change.

Help is at hand

Fortunately, these are problems we hope to tackle. CSIRO recently announced a five-year research partnership with Wine Australia, and one of the projects aims to adjust wine grape ripening to suit a changing climate.

We hope to do it by studying plant growth regulators (PGRs) – molecules that are used by the plant to control and coordinate development. We are using a class of PGRs called auxins, first studied in grass seedlings by Charles Darwin in the 1880s, that have important roles in vine growth, and the timing of grape growth and ripening.

Plant growth regulators can help control ripening times.
Shutterstock

By spraying these compounds onto vines and grapes shortly before ripening, auxins can potentially be used to influence the timing of this process and therefore harvest date. They are already used in other horticultural crops, such as to control fruit drop in apples and pears.

Applying very small amounts of auxin can delay grape ripening, and therefore harvest timing, by up to four weeks (Davies et al., 2015, J Ag Food Chem 63: 2137-2144). This treatment works for red and white varieties in hot or cool climates, and is safe, cheap and easy to apply.

The flavour and aroma of wines made from ripening-delayed grapes is largely indistinguishable from wines made from untreated fruit harvested at the same sugar level, up to a month earlier. An exciting exception is that, in Shiraz, auxin-induced ripening delay can be used to increase the concentration of rotundone, the compound responsible for this variety’s popular peppery notes.




Read more:
State of the Climate 2018: Bureau of Meteorology and CSIRO


Work is currently under way to fine-tune spray formulations and application times. The aim is to release a commercially available product within the next five years.

This kind of solution will be vital for the sustainable, economical production of high-quality wines from existing grape varieties in established wine growing regions. We hope it will ensure you can enjoy your favourite drop for many years to come.The Conversation

Christopher Davies, Team Leader, CSIRO and Christine Bottcher, Research scientist, CSIRO

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

Rising extreme weather warns of ecosystem collapse: study


Alfredo Huete, University of Technology Sydney and Xuanlong Ma, University of Technology Sydney

The world’s climate is already changing. Extreme weather events (floods, droughts, and heatwaves) are increasing as global temperatures rise. While we are starting to learn how these changes will affect people and individual species, we don’t yet know how ecosystems are likely to change.

Research published in Nature, using 14 years of NASA satellite data, shows eastern Australia’s drylands are among the most sensitive ecosystems to these extreme events, alongside tropical rainforests and mountains. Central Australia’s desert ecosystems are also vulnerable, but for different reasons.

As the world warms, this information can help us manage ecosystems and to anticipate irreversible changes or ecological collapse.

Maps created using satellite data to show which ecosystems are most sensitive to climate (orange) and least sensitive (green). Both could be worrying as the world warms.
Seddon et al.

Tipping points

Ecological theory tells us that as ecosystems become unhealthy, they approach critical thresholds (also referred to as tipping points). The more unhealthy they become, the quicker they respond to disturbances.

Ecosystems that cross a critical threshold are transformed into new states, often with losses in biodiversity, exotic species invasions, and sudden forest die-off events. For example, over the past 10 years, ecosystems in the western US have experienced large-scale tree deaths and native, black grama grasslands have been transformed to the exotic, South African Lehmann lovegrass.

Farms and crops can be thought of as agricultural ecosystems, and they are highly sensitive to variations in climate. This means they are very challenging to manage for sustainable livestock and crop production under such intensifying conditions of sudden good and bad periods.

As humans we show weakened resistance when we are sick, and we become more susceptible to external conditions. Similarly, slower than normal ecosystem responses to external changes may also be indicative of an unhealthy ecosystem.

Both of these measures, fast and slow, are early warning signs for ecosystem collapse.

Seeing ecosystems from space

But how do we know if an ecosystem is going to collapse? Space offers a unique vantage point. The new research uses data from NASA’s Moderate Resolution Imaging Spectroradiometer (or MODIS) satellites. The satellites, orbiting roughly 900 km above Earth’s surface, measure things like snow and ice, vegetation, and the oceans and atmosphere.

The satellites measure ecosystem “greenness”, which indicates how much an ecosystem is growing. This is not too different from a farmer visually interpreting cues of plant health based on colour, except that satellites can have the capability to analyse colour in parts of the spectrum beyond our sensing capabilities.

The researchers developed a “Vegetation Sensitivity Index”, which showed how ecosystems responded to changes in climate. They particularly looked at changes in temperature, cloud cover, and rainfall.

One nice aspect of this research is that it specifically shows which climate component has the biggest role in changing ecosystems. For example changes to alpine meadows were attributed to warming temperatures, while tropical rainforests were very sensitive to fluctuations in solar radiation (or cloud cover).

Australia’s dry ecosystems show dramatic changes between wet and dry. This is spinifex grassland during the dry. Spinifex covers around 20% of Australia’s land area.
James Cleverly, Author provided

Mulga woodland during a wet period.
James Cleverly, Author provided

Australia’s vulnerable ecosystems

Eastern Australia’s dry woodlands and semi-arid grasslands, according to the study, are some of the most sensitive ecosystems to climate change, alongside tropical rainforests and alpine regions. The main factor in Australia is water.

This is in line with our recent study conducted in southeast Australia since 2000, which shows sudden, abrupt shifts in ecosystem function over many semi-arid ecosystems. This demonstrated the vulnerability of eastern Australian ecosystems to climatic variability and future extreme climatic events.

The new study also found central Australia’s deserts and arid lands show unusually slow responses to climate variability, which is concerning. Slower responses may be an early warning that these ecosystems are approaching a critical threshold before collapsing.

But this might also be an adaptation to the extreme climate variability these ecosystems already experience. The vegetation “knows” that the good, rainy times don’t last and therefore they may not invest in new growth that will later become a burden when drought returns.

What does this mean for ecosystems?

This research isn’t the end of the story. Although satellite data are valuable, they can’t tell us exactly what are the causes or mechanisms of ecosystem change. To do that, we need information on the ground, and consistent data over long periods of time is hard to come by. One example is Australia’s Terrestrial Ecosystem Research Network, or TERN.

The next step is to attribute the reasons why some systems appear to be more sensitive than others and more importantly, predict where and when the critical transitions will occur.

When forests, grasslands, and other ecosystems approach their critical thresholds, their resistance is weakened and they become highly susceptible to insects, pests, disease, species invasions, and mortality. One way to help ecosystems cope may be to reduce pressures on the land, such as recreation, harvesting and grazing.

If ecosystems collapse, we can mitigate some of the damage by helping wildlife and minimising soil erosion and runoff following tree deaths. But the most important thing is recognising that each ecosystem will behave differently; some may collapse, but others will survive.

The Conversation

Alfredo Huete, Professor, Plant Functional Biology & Climate Change, University of Technology Sydney and Xuanlong Ma, Research Associate in Remote Sensing of Environment, University of Technology Sydney

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

Melting Antarctic ice sheets and sea level rise: a warning from the future


Andrew Glikson, Australian National University

The remote location of the Antarctic and Greenland polar ice sheets may leave us with the impression that developments in these regions have little effect on the climate and life in the temperate zones of the Earth, where most of us live. We may therefore be forgiven for asking why should we care when these changes are projected to unfold over tens to hundreds of years.

However, the stability of the polar regions is critical for maintaining a planet with the conditions that allowed the emergence of humans, agriculture and civilisation, as well as many other species. The polar ice sheets serve as “thermostats” of global temperatures from which cold air and cold ocean currents emanate, moderating the effects of solar radiation. The ice sheets regulate sea levels, store volumes of ice whose melting would raise sea level by up to 61 metres.

Unfortunately, what’s happening with the polar ice sheets now ought to warn humanity of what is to come.

For example, a recent paper suggested that melting Antarctic ice sheets could lead to 0.6-3.0 m of sea level rise by the year 2300. This is based on modelling of greenhouse gas emissions out to 2300.

If greenhouse gas emissions continue unchecked, the world may warm by 8–10℃ by 2300. Such a temperature rise could raise sea levels by tens of meters over hundreds of years.

The recent paper only looked at sea level rise from melting Antarctic ice sheets and does not take into account sea level rise contributions from the Greenland ice sheet (currently about 280 billion tonnes per year), which would more than double the Antarctic contribution.

Antarctic warming: Red represents areas where temperatures have increased the most during the last 50 years, particularly in West Antarctica.
NASA

Peering into the past to see the future

Much of the discussion in the paper and related papers appears to assume linear global warming – that is, little change to the rate of warming over time.

Little mention is made of feedbacks which could increase the rate of warming. Such feedbacks could arise from reducing albedo, where solar radiation usually strongly reflected by ice is replaced by strong absorption by water.

Other feedback processes associated with warming include methane release from permafrost and bogs; loss of vegetation; and fires.

In a recent article, former NASA climate scientist James Hansen and a large group of climate scientists point to observations arising from detailed studies of the recent history of the atmosphere-ocean-ice sheet system.

The climate records of the past — specifically, the Holocene (from about 10,000 years ago) and the Eemian interglacial period (about 115,000 to 130,000 years ago) — are closely relevant to future climate projections. These records include evidence for rapid disintegration of ice sheets in contact with the oceans as a result of feedback processes resulting in sea level rise to 5-9 m above current levels. All this during a period when mean global temperatures were near to only 1℃ above pre-industrial temperatures.

Sea levels reflect the overall global temperature and thus of global climate conditions. As shown by the position of the circles in the chart below, the ratio of sea level rise (SL) to temperature rise (TR) during the glacial-interglacial cycles was approximately between 10-15 metres per 1℃.

Plots of Temperature rise (relative to the pre-industrial age) vs relative sea level rise in (meters).

By contrast from around 1800 to the present sea level rose by an approximate ratio of 0.2-0.3 m per 1℃. This suggests significant further rise towards an equilibrium state between sea level and temperature. Thus, the points in the right-hand circle represent long-term temprature-sea level equilibria in the past while points in the left-hand circle represent where we’re at now, namely at an incipient stage moving toward future temprature-sea level equilibrium.

Why should long term climate change matter?

Due to the extreme rate of CO₂ and temperature rise during the 20th century relative to earlier events and the non-linearity of climate change trends the timing of sea level rise may be difficult to estimate.

Even on conservative estimates, current global warming is bound to have major consequences for human civilisation and for nature, as follows:

  • Further melting of the ice sheets will destroy the climate conditions which allowed agriculture and the rise of civilisation in the first place.

  • The lower parts of the world’s great rivers (Po, Rhine, Nile, Ganges, Indus, Mekong, Yellow, Mississippi, Amazon), where more than 3 billion people live and the bulk of agriculture and industry are located, sit no more than a few metres above sea level.

  • Further melting of the Antarctic and Greenland ice sheets can only result in sea level rises on the scale of tens of metres, changing the continent-ocean map of Earth.

Global temperatures have already risen 0.9℃ and continental temperatures 1.5℃ degrees above pre-industrial levels. If we account for the cooling effect of sulphur aerosols from industrial pollution, greenhouse gases have already contributed 2℃ of global warming. The current rate of global warming, faster than any observed in the geological record, is already having a major effect in many parts of the world in terms of droughts, fires, and storms.

According to James Hansen burning all the fossil fuels on Earth would result in warming of 20℃ over land areas and a staggering 30℃ at the poles, making “most of the planet uninhabitable by humans”.

In 2009 Joachim Hans Schellnhuber, Director of the Potsdam Climate Impacts Institute and Climate Advisor to the German Government, stated: “We’re simply talking about the very life support system of this planet”, constituting one of the most critical warnings science has ever issued to our species.

Mitigation plans proposed by governments would slow down the rate of carbon emissions but continuing emissions as well as feedbacks from ice melt, warming oceans, methane release and fires would continue to push temperatures upwards.

An effective technology required for global cooling efforts, if technically possible, would require investment on a scale not less than the trillions of dollars currently poured into armaments and war in the name of defence (more than $1.6 trillion in 2014).

Which planet do current decision makers think we are living on?

The Conversation

Andrew Glikson, Earth and paleo-climate scientist, Australian National University

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

Australia: NSW – Fire Ants in Sydney


The link below is to an article warning of a Fire Ant invasion of Sydney – this is a very important problem and warning for Sydney.

For more visit:
http://www.mygc.com.au/news/fire-ant-invasion-poses-higher-risk-than-sharks/