Climate models – why they’re not just hot air

We rely a lot on climate models. They not only help us understand our present climate, but also allow us to understand possible future conditions and how different regions of our planet are likely to be impacted by climate change.

Having access to this information is vital for the community, government and industries to make informed decisions – sectors like tourism, farming and transportation to name a few.

As useful as these tools are, the reality is that the Earth’s climate system is incredibly complicated. It is affected by an infinite number of variations in the atmosphere, land surface, oceans, ice, and biosphere.  How these factors interact with one another, and our socio-economic decisions, further complicates the issue.

Our climate system is affected by variations in the atmosphere, land surface, oceans, ice and biosphere.

Our climate system is affected by variations in the atmosphere, land surface, oceans, ice and biosphere.

In the absence of a twin Earth to use as an experimental control, simulations are the only method we have to understand the future.

Using observed data, advanced algorithms and software systems, scientists have been developing and refining these valuable climate models for years. However in recent times, there has been conjecture about a key aspect of the reliability of these models; whether they are accurately predicting temperature trends?

A new study, published today in Nature Climate Change, shows that yes in fact, they are.

According to the study’s lead author Dr James Risbey, the key to evaluating decadal climate variations  is recognising the difference between climate forecasts and climate projections.

He explains that climate forecasts track the detailed evolution of a range of factors, including natural variations like El Niño and La Niña (which put simply is, warm water sloshing around the ocean). This is important because in El Niño and La Niña dominated periods, temperature trends will naturally speed up and slow down.

climate model

A visualisation of temperature projections for a mid-level greenhouse gas emission scenario (ACCESS)

“Climate projections, on the other hand, capture natural variations, but have no information on their sequence and timing. Since these can impact the climate on a short timescale as much as human activities, their omission from projections creates a mismatch with observed trends. In other words, comparing the two wouldn’t pass the old ‘apples with apples’ test,” he said.

For this latest study, James and his colleagues looked at a range of different climate models that were in phase with natural variability. In doing so, they were able to make meaningful comparisons between model projections and observed trends.

Their analysis showed that in these instances climate models have been very accurate in predicting trends in our climate over the past half century. In other words, climate change models are a lot more than hot air.

Fine out more about our research into climate in our recent report State of the Climate: 2014.

Media Contact: Simon Torok +61 409 844 302 or simon.torok@csiro.au


Drought in store as El Niño’s western cousin to grow stronger

Dried up lake

Drought conditions are set to become more frequent with the changing behaviour of the Indian Ocean. Image: Wikimedia / Peripitus

By Agus Santoso and Wenju Cai, CSIRO

Over the past few months, a lot of attention has been paid to the potentially strong El Niño event brewing in the Pacific Ocean. But there is also the potential for an emerging climate phenomenon in the Indian Ocean that could worsen the impacts of an El Niño, bringing drought to Australia and its neighbours.

The Indian Ocean Dipole is a phenomenon that has already been shown to have a significant impact on rainfall in countries bordering the Indian Ocean.

The main effects are drought in Australia, while east Africa suffers floods. And our new work published in the international journal Nature today shows that the frequency of these extreme events is set to increase as the world warms this century.

See-saw pattern

The Indian Ocean Dipole is a year-to-year see-saw pattern in surface temperature and rainfall across the tropical Indian Ocean. During a positive Indian Ocean Dipole phase, sea surface temperatures off Sumatra and Java in Indonesia are colder than normal. Meanwhile, off east Africa, surface waters are unusually warm.

Like an El Niño, a positive Indian Ocean Dipole brings heavy rainfall to eastern parts of Africa and drought to countries around the Indonesian Archipelago, including Australia. A negative Indian Ocean Dipole phase tends to do the opposite.

General view of the Gash River flooding in Kassala, Eastern Sudan

Double trouble

When a positive Indian Ocean Dipole is coupled with an El Niño event, rainfall declines are more widespread across Australia, and more intense, particularly in the southeast.

Currently, as we move into Australia’s winter, the outlook is for a neutral Indian Ocean Dipole in October. But some models are projecting the development of a positive Indian Ocean Dipole. This should not come as a surprise. Over the past 50 years, around 70% of positive Indian Ocean Dipole events coincided with an El Niño event.

Predicting an Indian Ocean Dipole event is more difficult than forecasting an El Niño. Like an El Niño, autumn conditions create a barrier that prevents forecasters from being able to predict accurately what state an Indian Ocean Dipole will be — positive, negative or neutral at its peak. This is because its development relies on easterly winds off Sumatra and Java which occur after autumn, and usually last until November.

So, unlike an El Niño, which peaks in summer, Indian Ocean Dipole events form in winter and then peak in spring. This creates a narrower predictability window that gives little warning to industries, such as farming, that depend on rain through spring.

What’s more, because of the strong monsoon seasonality, these events do not have a prominent warm water volume that an El Niño has as a precursor to the event, so there is no time to see the event unfolding. This is also partly because the Indian Ocean is smaller than the Pacific and is bounded by Asia to the north, which prevents a slow, large accumulation of heat like that seen in the Pacific.

In 2012, while conditions in the Pacific Ocean suggested an emerging El Niño, a positive Indian Ocean Dipole abruptly developed in July. The El Niño that year dissipated before it was expected to peak in summer 2013. The preceding two consecutive strong La Niñas helped to alleviate the Indian Ocean Dipole’s drying impact on Australia. But it could still have played a role in the January 2013 bushfires in southeastern Australia by drying out soils.

What the future holds

Just like an El Niño, Indian Ocean Dipole events can vary in size. Our work in Nature today shows that extreme positive Indian Ocean Dipole events are characteristically distinct from moderate ones.

During an extreme event, the cold waters off Sumatra extend farther west along the equator as ocean currents and winds reverse their flow and head towards eastern Africa. This makes the western part of the Indian Ocean warm even more strongly than during moderate events.

Our research shows that global warming is likely to triple the number of these extreme events. This would increase the frequency of droughts over the southern parts of our continent. The research follows another recent study that showed extreme El Niño events were also likely to increase with global warming.

Even though the two climate phenomena are not directly connected, it makes sense that both would increase in frequency under global warming. This is because under a warmer climate, the Walker Circulation, which creates easterly winds in the tropical Pacific and westerly winds in the tropical Indian Ocean, is predicted to weaken.

This weakening will create a faster warming rate in the western Indian Ocean than in the east. As a result, westerly winds and ocean currents at the Equator weaken and so they can more easily reverse direction. This is exactly the environment needed in the Indian Ocean to create an extreme positive Indian Ocean Dipole and in the Pacific Ocean to enable the development of extreme El Niño events.

Deadly floods and droughts

Extreme positive Indian Ocean Dipole events are unusual and have only occurred three times in recent decades: in 1961, 1994 and 1997. Of these three, only the 1997 event coincided with a significant El Niño event. This El Niño turned out to be the strongest ever recorded in the 20th century.

Remarkably, Australia was spared the worst of this extreme combination, but other countries in our region and in Africa were not so lucky. There were devastating floods in Somalia, Ethiopia, Kenya, Sudan and Uganda that killed thousands and displaced hundreds of thousands.

Indonesia suffered a serious drought that led to famine, riots and fires that caused smoke haze to spread across Singapore, Malaysia and Thailand.

It is not inconceivable that the drought may have been one of the factors behind the political instability that brought down the Suharto government in 1998.

What’s in store this year?

At the beginning of June this year, the conditions in the Pacific Ocean are still on track to cross the threshold for an El Niño. The characteristics of this developing event suggest we could be in for a significant El Niño this summer. With models starting to suggest a possible development of a positive Indian Ocean Dipole, could we be moving into a situation like the 1997 event? We hope not.

The picture will become clearer over the coming months, but it is vital that we prepare for this potential event. More importantly still, we need to get ready for these extreme events to become more common as global warming continues in the coming decades.

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


The economics of adaptation: protecting people, prosperity and environment in a warming world

By Dr Paul E Hardisty

Paul Hardisty

Dr Paul Hardisty

For a long time, people were hesitant to discuss adapting to climate change. Some called it defeatist, others worried it would be used as an excuse to delay action on emissions reduction. That was a long time ago. The science of climate adaptation – developing tools, systems and technologies that improve the ability of communities and businesses to survive and prosper as the climate changes around them – has come a long way.

What emerges from this substantial and growing body of work are four powerful yet simple conclusions:

First: adapting to climate change is about people.

As the world warms, people are exposed to greater levels of risk. The State of the Climate 2014 report, recently released by CSIRO and the Bureau of Meteorology, shows that climate change is here and is happening now . The risk of bushfires has increased. Communities are more exposed to extreme heat. Over the past several years, extreme flooding in Australia has caused incalculable suffering. Without serious action to reduce emissions, these trends will strengthen. Adaptation means protecting people from the impacts already occurring and that we’ll see in future by changing the way we plan, design, and operate the places we live: keeping cities cooler by retaining and enhancing urban tree canopies and greenspaces; building houses to current fire codes; continuing to improve our ability to predict fire weather and provide early warning so communities can prepare; planning housing development to avoid exposed floodplains and retrofitting existing buildings to ensure survivability. Adaptation saves lives.

Second: adapting to climate change is good business.

During the recent Queensland floods, mines were flooded, rail lines washed out, and power disrupted, resulting in hundreds of millions of dollars in lost production. Studies by Stern, Garnaut, and others estimate that climate change, unchecked, will cause economic losses in the billions. CSIRO estimates that by 2070, the value of buildings in Australia exposed to climate-related events will exceed five trillion dollars. But carefully planned and timed adaptation can reduce the damage and cost impact of climate change on businesses and our economy by up to half, and in some cases more. Many businesses in Australia are already starting to plan resilience into their operations, driving down risk levels. But many have not, and remain significantly exposed. Adaptation, properly done, saves money.

People up to their waste in flood water

The floods in Brisbane, 2011. Image: Glenn Walker

Third: Adaptation is a good deal, but the longer we wait to act, the lower the benefits.

Many of the practical adaptive actions we can do to protect our families, communities and businesses are low cost, and yield significant improvements in resilience. Some adaptation measures, like preserving coastal ecosystems (dunes and mangroves, for instance), protect homes, coastal infrastructure and industry from storm surges and sea-level rise, and cost almost nothing. Building or retrofitting homes to current fire codes costs relatively little, and substantially improves survival rates. Recent CSIRO research shows that protecting buildings from coastal flooding can yield up to $40 in net benefit for each dollar invested. Another study on protecting infrastructure from high winds shows that net benefits of adaptation are large, but drop by half if we wait 20 years to implement. Act early, reap the rewards.

Fourth: There are economic and ecological limits to adaptation.

Adaptation is good news, and compared to the challenge of cutting emissions, much can be achieved quickly and with little fuss. But it is important to recognise that there are limits to what adaptation can do.

There are economic limits. We will exhaust the lowest cost – highest benefit adaptation options first. Dunes and mangroves are great, if you have them, but they can only do so much. As the climatic changes persist and worsen, as is projected, other measures will be needed. Sea walls and tidal barriers can help protect coastal communities from sea-level rise and storms. But they can pose significant engineering challenges, and carry big price tags. In the next few decades, with business-as-usual emissions, the costs of adaptation could start not only to stress the ability of society to pay, but could begin to surpass the cost we would have had to pay to transform our energy systems in the first place.

There are ecological limits, too. While there are things we can do to help reduce the impacts on species and ecosystems, like planning reserves to provide corridors for migration, and transplanting vulnerable species into refuges in new suitable locations, the rates of ecosystem change implied by our current emissions trajectory will leave many creatures behind. Landmark work done by CSIRO predicts that at current emission rates, virtually every native ecosystem in Australia will have been replaced by something else by 2070.

Adaptation makes sense, on a number of levels. Understanding the practical and economic limits of adaptation will help us frame the case for emissions reduction, highlight the risks we face, and show the importance of starting our adaptation journey now.

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The Intergovernmental Panel on Climate Change Working Group II released its Fifth Assessment Report on climate change impacts, adaptation and vulnerability today. In this video Dr Mark Howden discusses how CSIRO is developing strategies to help reduce the impacts of climate change on ecosystems and communities:


State of the Climate 2014? It’s warmer.

State of the Climate 2014 report cover

Every two years CSIRO and the Bureau of Meteorology get together, crunch the numbers and release a definitive report on long term trends in Australia’s climate – The State of the Climate.

The SoC 2014 released today is focused on the changes that have been observed in Australia’s long-term climate trends and it shows that temperatures across Australia were, on average, almost 1°C warmer than they were a century ago, with most of the warming having occurred since 1950.

“Australia’s mean temperature has warmed by 0.9°C since 1910,” BoM chief Dr Vertessy said. “Seven of the ten warmest years on record in Australia have occurred since 1998. When we compare the past 15 years to the period 1951 to 1980, we find that the frequency of very warm months has increased five-fold and the frequency of very cool months has decreased by around a third.

“The duration, frequency and intensity of heatwaves have increased across large parts of Australia since 1950. Extreme fire weather risk has increased, and the fire season has lengthened across large parts of Australia since the 1970s.

“We have also seen a general trend of declining autumn and winter rainfall, particularly in southwestern and southeastern Australia, while heavy rainfall events are projected to increase. Australian average annual rainfall has increased slightly, largely due to increases in spring and summer rainfall, most markedly in northwestern Australia.”

History of data collection

State of the Climate 2014 draws on an extensive record of observations and analysis from CSIRO, the Bureau of Meteorology, and other sources.

CSIRO boss Megan Clark said Australia has warmed in every State and Territory and in every season.

“Australia has one of the most variable climates in the world. Against this backdrop, across the decades, we’re continuing to see increasing temperatures, warmer oceans, changes to when and where rain falls and higher sea levels,” Dr Clark said. “The sea-surface temperatures have warmed by 0.9°C since 1900 and greenhouse gas concentrations continue to rise.”

CSIRO and the Bureau of Meteorology play a key role in monitoring, measuring and reporting on weather and climate, contributing to improved understanding of our changing global climate system. State of the Climate 2014 is the third report in a series and follows earlier reports in 2010 and 2012.

Indicators of a world experiencing a consistent pattern of warming.

Indicators of a world experiencing a consistent pattern of warming.

Below are some of the main facts from the report.

Temperature

  • Australia’s mean surface air temperature has warmed by 0.9°C since 1910.
  • Seven of the ten warmest years on record have occurred since 1998.
  • Over the past 15 years, the frequency of very warm months has increased five-fold and the frequency of very cool months has declined by around a third, compared to 1951–1980.
  • Sea-surface temperatures in the Australian region have warmed by 0.9°C since 1900.

Rainfall

  • Rainfall averaged across Australia has slightly increased since 1900, with a large increase in northwest Australia since 1970.
  • A declining trend in winter rainfall persists in southwest Australia.
  • Autumn and early winter rainfall has mostly been below average in the southeast since 1990.

Heatwaves and fire weather

  • The duration, frequency and intensity of heatwaves have increased across large parts of Australia since 1950.
  • There has been an increase in extreme fire weather, and a longer fire season, across large parts of Australia since the 1970s.

Global atmosphere and cryosphere

  • A wide range of observations show that the global climate system continues to warm.
  • It is extremely likely that the dominant cause of recent warming is human-induced greenhouse gas emissions and not natural climate variability.
  • Ice-mass loss from the Antarctic and Greenland ice sheets has accelerated over the past two decades.
  • Arctic summer minimum sea ice extent has declined by between 9.4 and 13.6 per cent per decade since 1979, a rate that is likely unprecedented in at least the past 1,450 years.
  • Antarctic sea-ice extent has slightly increased by between 1.2 per cent and 1.8 per cent per decade since 1979.

Oceans

  • The Earth is gaining heat, most of which is going into the oceans.
  • Global mean sea level increased throughout the 20th century and in 2012 was 225 mm higher than in 1880.
  • Rates of sea-level rise vary around the Australian region, with higher sea-level rise observed in the north and rates similar to the global average observed in the south and east.
  • Ocean acidity levels have increased since the 1800s due to increased CO2 absorption from the atmosphere.

Greenhouse gases

  • Atmospheric greenhouse gas concentrations continue to increase due to emissions from human activities, with global mean CO2 levels reaching 395 ppm in 2013.
  • Global CO2 emissions from the use of fossil fuel increased in 2013 by 2.1 per cent compared to 3.1 per cent per year since 2000.
  • The increase in atmospheric CO2 concentrations from 2011 to 2013 is the largest two-year increase ever observed.

Future climate scenarios for Australia

  • Australian temperatures are projected to continue to increase, with more hot days and fewer cool days.
  • A further increase in the number of extreme fire-weather days is expected in southern and eastern Australia, with a longer fire season in these regions.
  • Average rainfall in southern Australia is projected to decrease, with a likely increase in drought frequency and severity.
  • The frequency and intensity of extreme daily rainfall is projected to increase.
  • Tropical cyclones are projected to decrease in number but increase in intensity.
  • Projected sea-level rise will increase the frequency of extreme sea-level events.

Download the full report on our website. Follow the conversation on Twitter with #SoCAus

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Media: Huw Morgan  M: +61 417 834 547


Most Australians overestimate how ‘green’ they really are

More than half of Australians say they recycle for mostly environmental reasons. Image: Shutterstock/spwidoff.

More than half of Australians say they recycle for mostly environmental reasons. Image: Shutterstock/spwidoff.

By Zoe Leviston, Research Scientist

Most Australians overestimate how much they are doing for the environment compared to others, and are more concerned about water shortages, pollution and household waste than climate change, a new CSIRO survey reveals.

Taken over a period of July to August last year, it is the latest in a series of annual national surveys on Australians’ attitudes to climate change involving more than 5000 people from across urban, regional, and rural Australia. (You can read about past survey results here and here.)

More than 70% of people said they thought climate change was an important issue, which has remained consistently the case since we first asked this question in 2010.

However, compared to many other issues including health, costs of living and other environmental issues such as drought, we found that climate change was considered to be much less of a concern.

Biased towards ourselves

The way we perceive ourselves and others can influence how we respond to contested issues, including climate change. However, these perceptions are subject to cognitive biases or distortions as we attempt to make sense of the world around us.

Misperceptions about what others think about climate change extend to misperceptions about what others do.

One of the questions we asked people in this latest survey was what they were doing in their everyday lives to respond to climate change, and why.

For example, did they always recycle their household waste, had they installed solar panels, or had they changed their diet? The results are shown below.

What environmental actions people said they were doing in their everyday lives.

What environmental actions people said they were doing in their everyday lives.

When we added up all the actions people said yes to (regardless of why they were doing them), we found a normal distribution of responses: a few people did not much of anything; quite a lot of people did a moderate amount; and a few people did a great deal.

We then asked our respondents this question: “How much do you think you do compared to the average Australian: a lot less, a little less, about the same, a bit more, or a lot more?” Here’s what they said.

How much environmental action the survey respondents thought they took, compared with an average Australian.

How much environmental action the survey respondents thought they took, compared with an average Australian.

So how good were our 5000 respondents at guessing how they compared with others? To find out, we cross-referenced what people said they did with their estimates of how they compared with an average Australian.

Just under one-quarter (21.5%) got it about right: regardless of how many actions they performed, their assessment of where they stood in relation to other people was fairly accurate.

The same amount (21.5%) were what we might call “self-deprecating”: they undervalued their comparative performance.

But more than half our participants (57.1%) were “self-enhancing”: they tended to overestimate how much environmental action they were compared to others.

Research tells us that it’s not just the environment where we tend to think we’re better than others.

The “better than average effect” describes our predisposition to think of ourselves as exceptional, especially among our peers. The effect reflects our tendency to think of ourselves as more virtuous and moral, more compassionate and understanding and (ironically) as less biased than other people.

In a famous example, when people were asked to assess their own driving ability relative to peers, more than three-quarters of people considered themselves to be safer than the average driver.

How important is climate change?

When we asked people how important climate change was, just over 70% of people rated it as “somewhat”, “very”, or “extremely” important. That importance rating has remained unchanged when we first asked this back in 2010.

But this year we also asked people to rank the importance of climate change relative to a list of 16 general concerns in society, including health, the cost of living, and the economy. When framed in these relative terms, climate change was ranked as the third least important issue.

How people ranked a list of general and environmental concerns.

How people ranked a list of general and environmental concerns.

Similar to previous years, we found the majority of respondents (81%) think the Earth’s climate is changing, and people are more likely to think that human activity is the cause (47%) as opposed to natural variations in temperature (39%). When we look at repeat respondents (those people who participated in more than one of our surveys), we find no significant changes since 2010, although there was a very slight increase in the small proportion of people who say they “don’t know”.

Other changes have been slight, but noteworthy. There has been an increase in the levels of responsibility individuals feel to respond to climate change. People have also become more trusting about information from environmental and government scientists.

Zoe Leviston does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

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

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Take a look at our video exploring the key findings of the survey:


What is this? A centre for ants?

Israel knows there's a lot more to life than being really, really, ridiculously good looking.

Israel knows there’s a lot more to life than being really, really, ridiculously good looking.

What do ants, Darwin and Texas have in common? Why, it’s Fullbright Scholar Israel Del Toro.

Israel has spent the past year with our Ecosystem Sciences team observing how the little critters in northern Australia are responding to global climate change.

Born and raised in Texas and currently studying at the University of Massachusetts, Israel was given the opportunity to work with us in Darwin because of his expertise in ant ecology.

He created statistical and geographical models to predict how our ant communities might react to regional climate change. This information will help us conserve habitats and species across different ecosystems.

Our very own centre for ants.

Our very own ‘centre for ants’ holds over 5000 different species.

Sadly, even our little ants aren’t immune to the warming climate. Around 25 per cent of species in Israel’s study showed major declines in their range and could possibly face extinction as their habitats change over the next 65 years.

Our Darwin lab (informally known as the centre for ants) was the perfect location for Israel to carry out his research. Here we hold the world’s most extensive collection of Australian ants with over 5,000 different species – now that’s something to brag about.

“Working with ants is what got me hooked on ecology research. But ant diversity in the US is quite small compared to the wealth of species found in Australia. So for me, coming here to expand on my research interests was a logical next step in my career.”

Israel has just returned to America to finish his PhD. He plans on defending his dissertation early next year and wants to start a postdoc soon afterwards.

“This year has really opened up new doors for me. Doing research and remote fieldwork in the Top End has been amazing. There’s nothing quite like accessing field sites in helicopters in places like Kakadu National Park.”

For more information on careers at CSIRO, follow us on LinkedIn.


Meet Peter, from Tornado Alley to the villages of Vietnam

Meet Peter Hoffmann: a champion of global climate research.

Peter’s passion for climate change has taken him all around the world – from Germany to Vietnam.

Meet Peter Hoffmann, a young climate scientist from Germany who has recently joined our Climate Adaptation Flagship in Melbourne.

Peter is using his analytical skills to tackle the global issue of climate change. It’s his job to run and analyse results from advanced climate models, which reproduce features of current and past climate changes. This will help us better understand and adapt to the changing climate.

His interest in climate change has taken him all over the world – from America’s Tornado Alley to rural Southeast Asia.

America's infamous tornado alley (red) and the related weather systems. Image: Dan Craggs.

America’s infamous tornado alley (red) and the related weather systems. Image: Dan Craggs.

Peter completed his PhD in Meteorology at the University of Hamburg, studying the impact of the urban heat island effect. This occurs when a metropolitan area is significantly warmer than its surrounding rural areas due to human activities.

Peter (right) is mentoring early career scientists as part of his work in Vietnam.

Early career scientists who Peter (right) has recently mentored.

And now Peter is continuing his work in Vietnam. Here he is reviewing the impacts of climate change on the country, looking at how heatwaves and droughts are likely to change in the future.

He is also mentoring and training early career scientists to help expand their knowledge in this field.

So why choose a career in climate science?

“I wanted to research something where I can see, feel and experience the effects of what I’m analysing. This work has such practical outcomes,” says Peter.

“I’ve always been fascinated by the forces of nature, so this job is the perfect fit for me.”

Learn more about our work on climate science.

For more information on careers at CSIRO, follow us on LinkedIn.


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