Winter is coming, and it’s looking mighty mild

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Brrr! It’s cold in here!
Alpha/Flickr, CC BY-SA

Jonathan Pollock, Australian Bureau of Meteorology and Andrew B. Watkins, Australian Bureau of Meteorology

After an exceptionally warm and dry autumn, it’s time to look ahead to see what’s in store for winter. The Bureau of Meteorology’s climate outlooks for winter, issued today, shows above-average temperatures and below-average rainfall are likely across southern Australia. While some of us will relish the prospect of a mild winter, the dry isn’t necessarily good news for everyone.

Read more:
When is it going to snow? Getting a fix on what can make a good season

Warm lead-up to winter

Summer-like conditions continued into early autumn for much of southern Australia, including an exceptional heatwave in early April. Temperatures in autumn were warmer than average across much of the continent. New South Wales, South Australia, Western Australia and Victoria all experienced one of their warmest autumns since at least 1900. Overnight temperatures have also been warmer than average in most parts.

Autumn maximum temperature map.
Bureau of Meterology

Very dry autumn for the southern mainland

For many southern areas autumn wasn’t just warm, it was also extremely dry. New South Wales, Victoria, southwest Western Australia and South Australia all had one of their driest autumns on record.

Many farmers in southern Australia look to the autumn break – the first significant rain event (25mm or more) after summer – to kick off the crop and pasture growing season. The autumn break arrived by mid-May across southern Victoria, eastern New South Wales and southwest coastal Western Australia. However, farmers in northwest Victoria, inland New South Wales, eastern South Australia and much of inland Western Australia didn’t receive an autumn break this year.

One of reasons for the warm and dry autumn in the south was higher than average pressure over southern Australia. The high pressure meant rain bearing cold fronts from the Southern Ocean couldn’t push up into southern Australia.

Autumn rainfall map.
Bureau of Meterology

No strong influence from Pacific or Indian Ocean this winter

So, will this pattern of warm and dry continue? Two of the major drivers of Australia’s climate, the El Niño–Southern Oscillation (ENSO) in the Pacific Ocean, and its equivalent in the Indian Ocean, the Indian Ocean Dipole (IOD), were neutral during autumn, and are likely to remain so throughout winter.

Read more:
Droughts and flooding rains: it takes three oceans to explain Australia’s wild 21st-century weather

Of the eight international climate models surveyed by the Bureau of Meteorology, seven predict winter will see ENSO-neutral sea surface temperatures in the central Pacific, with only one model forecasting a warming to El Niño levels by August.

Models also suggest the Indian Ocean Dipole (IOD) will remain neutral through winter. But there is quite a range of scenarios from the international modelling centres the Bureau assesses. One model is predicting a positive IOD over winter, one model predicting a negative IOD in spring, and the other four are neutral. Typically, when the ENSO and IOD are both neutral there is no strong shift in the outlook towards widespread wetter or drier conditions across most of Australia.

Read more:
Explainer: El Niño and La Niña

Most international model outlooks for the ENSO sea surface temperature index in the central Pacific Ocean (NINO3.4) remain neutral in August.
Model outlooks provided by: BoM (Bureau of Meteorology), CanSIPS (Canadian Seasonal to Interannual Prediction System), ECMWF (European Centre for Medium-Range Weather Forecasts), JMA (Japan Meteorological Agency), Météo France, NASA (National Aeronautics
Most international model outlooks for the IOD sea surface temperature index remain neutral in August.
Model outlooks provided by: BoM (Bureau of Meteorology), CanSIPS (Canadian Seasonal to Interannual Prediction System), ECMWF (European Centre for Medium-Range Weather Forecasts), Météo France, NASA (National Aeronautics and Space Administration), and the

However, when these major drivers are neutral, other factors can have a greater influence on Australian rainfall and temperature patterns. For instance, forecast warmer-than-usual temperatures in the Tasman Sea and the associated lower-than-normal air pressure this winter is likely to contribute to a weakening of westerly winds over southern Australia that would normally draw cold fronts up from the Southern Ocean.

Read more:
The BOM outlook for the weather over the next three months is ‘neutral’ – here’s what that really means

So, what’s the outlook for winter?

As a result of the weakened westerly winds, below-average winter rainfall is likely for western parts of Western Australia, and for most of New South Wales extending across the border into southern Queensland and northern Victoria. For most other parts, the outlook is neutral, meaning roughly equal chances of above- or below-average rainfall.

The outlook for June is looking particularly dry across most of the southern mainland.

The likely reduction in cold fronts, and clearer skies over much of the continent means warmer-than-average temperatures are favoured across southern Australia, with the strongest likelihood (about 80%) in the southeast.

The model suggests there is also an above-normal likelihood of winter “mildwaves” – periods of very mild weather – along Australia’s southeast coast.

Read more:
Winter heatwaves are nice … as extreme weather events go

So, what does this all mean? For farmers and those working in the agricultural sectors, the warmer temperatures mean soils will stay warm longer. This is likely to keep the crop and pasture growing window open a little longer before the cold of winter. Dry conditions are likely to mean a slow and possibly late start to the growing season, potentially pushing the crop harvest later into the warmer months of 2018, when heatwaves can become a problem.

What does this mean for the snow season?

For skiers, a later start to the season becomes more likely with a warm and dry June expected. On the other hand, neutral ENSO conditions typically bring snow cover that’s a little deeper than average by mid-season.

This is a contrast to strong El Niño or La Niña phases, which both typically mean less snow than usual, but for different reasons. El Niño phases mean less rainfall and warmer days during the snow season. La Niña years usually have more rain, but temperatures can be too high for snow to form.

This has happened more often in recent decades because of climate change. Historically, neutral years have had more consistent good snow depths than either El Niño or La Niña years, so late winter should be a good time to hit the slopes.

The ConversationFor more details on the long-range forecast for winter, visit our Climate Outlooks website and subscribe to Climate Outlooks to stay on top of what’s happening with the climate. A complete set of Climate Summaries covering May and autumn 2018 will be available on 1 June.

Jonathan Pollock, Climatologist, Australian Bureau of Meteorology and Andrew B. Watkins, Manager of Long-range Forecast Services, Australian Bureau of Meteorology

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


Ocean heat waves and weaker winds will keep Australia warm for a while yet

Jonathan Pollock, Australian Bureau of Meteorology; Andrew B. Watkins, Australian Bureau of Meteorology, and Catherine Ganter, Australian Bureau of Meteorology

The Australian Bureau of Meteorology’s latest climate outlook, issued today, suggests the above-average warmth of April is likely to extend into May, and for parts of the south, potentially into winter.

The outlooks for May temperatures show that both days and nights are likely to be warmer than average for much of Australia. Only northeast Queensland is likely to miss out on warmer temperatures, with no strong push there towards warmer or cooler conditions.

The unseasonable warmth, which has broken records in Adelaide and Sydney, appears to be driven by high ocean temperatures, and weaker westerly winds and much lower than average soil moisture across southern Australia.

Bureau of Meteorology

The rainfall outlook for May is mixed, but generally shows no strong shift towards a wetter or drier month for most of Australia.

Read more:
Winter heatwaves are nice … as extreme weather events go

By June the tendency for warmer than normal days may start to wane. This easing of the outlook for above average temperatures as we head into winter is reflected in the full May-July outlook, with only some parts of southern Australia likely to be warmer than average. Southern parts of Western Australia and South Australia have a moderate chance of warmer than average daytime temperatures, with stronger odds over southern Victoria.

The full May to July outlook shows a more balanced picture, with southern Australia more likely to experience higher than average temperatures.
Bureau of Meteorology

Odds don’t favour a strong push towards a particularly wet or dry three months for much of Australia, apart from some areas in the far southeast.

What’s behind the warmth?

The El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) are two of Australia’s major climate drivers. ENSO is currently in a neutral phase, meaning its neither El Niño nor La Niña. Our outlooks suggest it is likely to stay neutral leading into winter.

Read more:
Explainer: El Niño and La Niña

The IOD is also neutral, and most models suggest it will remain so over the coming months.

But given it is harder to forecast ENSO and the IOD in autumn compared to other times of the year, climatologists will be monitoring Indian and Pacific Ocean temperature patterns closely as we edge towards winter.

With near-average temperature patterns in the tropical oceans to our east and west, there is no strong shift in the outlook towards widespread wetter or drier conditions for Australia.

Rainfall during May is expected to remain essentially average.
Bureau of Meteorology

However, for temperatures it’s a little different. Sure ENSO and the IOD are playing a minor role right now, but other factors are coming into play.

Read more:
The BOM outlook for the weather over the next three months is ‘neutral’ – here’s what that really means

Ocean heat waves

Ocean temperatures in the Tasman Sea and around New Zealand are much warmer than average – in fact at record levels in the past few months – and are expected to remain warm over the coming months. These warm sea temperatures are associated with a large area of lower than usual air pressure to Australia’s east, which is likely to weaken the westerly winds that normally bring cooler air to southern Australia in autumn and winter.

Another factor in the current and forecast warmth is the very much below average soil moisture across southern Australia. With little moisture available to evaporate and cool the air, and the soils themselves not able to store as much heat, the air above the ground heats more rapidly in the daytime.

Bureau of Meteorology

In addition to our natural climate drivers, Australian climate patterns are being influenced by the long-term trend in global air and ocean temperatures. Winter maximum temperatures have increased by 1℃ over the past century, with three of the top five warmest winters in the past 108 years occurring since 2009. Oceans around Australia have warmed by slightly more, with four of our top five warmest years since 2010.

The ConversationSo while the normal big two drivers of our climate remain benign, it would actually be wrong to assume there will be a quick return to more average temperatures. The outlook released today suggests we may have to wait at least another month until service returns to normal for much of the country.

Jonathan Pollock, Climatologist, Australian Bureau of Meteorology; Andrew B. Watkins, Manager of Long-range Forecast Services, Australian Bureau of Meteorology, and Catherine Ganter, Senior Climatologist, Australian Bureau of Meteorology

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

Australia’s 2017 environment scorecard: like a broken record, high temperatures further stress our ecosystems

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It was a hot year for many Australians.
ABCNews/David McMeekin

Albert Van Dijk, Australian National University and Madeleine Cahill, CSIRO

While rainfall conditions were generally good across Australia in 2017, record-breaking temperatures stressed our ecosystems on land and sea, according to our annual environmental scorecard. Unfortunately, it looks like those records will be broken again next year – and again in the years after that.

Indicators of Australia’s environment in 2017 compared to the previous year. Similar to national economic indicators they provide a summary, but also hide regional variations, complex interactions and long-term context.

National Scorecard

Our terrestrial environment has done relatively well in 2017, mainly thanks to good rainfall and leftover soil moisture from the year before. However, such a short summary for a country the size of a continent is bound to hide large regional differences. 2017 was no exception.

Western Australia and the Northern Territory received good rains, with vegetation growth, river flows and wetland area all coming in above average. By contrast, Queensland and particularly New South Wales saw a reversal of the previous year’s gains.

Environmental Condition Score in 2017 by state and territory. The large number is the score for 2017, the smaller number the change from the previous year.
Based on data on

Climate change is here to stay

There was good news and bad news for our atmosphere in 2017. Humanity’s collective action to fix the hole in the ozone layer is proving successful. The hole is the smallest it has been since 1988.

On the other hand, global carbon dioxide concentrations rose again, by 0.5%. While this was less than in the previous two years, it was still far from enough to stop accelerating global warming.

Globally, 2017 was the second-warmest year on record after 2016. It was the third-warmest year for Australia, and the hottest year on record in southern Queensland. These statistics are all the more remarkable because 2017 was not an El Niño year, during which high temperatures more commonly occur.

The world’s oceans were the hottest they’ve been since measurements started. Sea levels rose by 6.4mm, and sea ice cover at the poles reached another record low. In short, our planet is warming.

Read more:
Climate change’s signature was writ large on Australia’s crazy summer of 2017

The main events

Last year broke the most high-temperature records since 2009, which was at the height of the Millennium Drought – the worst drought since European settlement.

Queensland and northern New South Wales were affected most, with summer heatwaves in February and a second round of bleaching on the Great Barrier Reef. In March, Cyclone Debbie rammed into the Great Barrier Reef and the Queensland coast, bringing torrential rains and widespread flooding in its wake. The cyclone helped cool down the shallow reef waters but also ravaged delicate corals in its path, stirred up sediment and caused rivers to flush more damaging sediment and nutrients out to sea.

Winter was dry and the warmest on record and September also set heat records. Experts predicted the risk of a bad summer fire season, which did not happen, thanks to a combination of mild weather and well-timed rainfall. Nationally though, the number and size of fires were still above average, mainly due to good growing conditions in WA’s arid rangelands.

Tree growth hides loss of forests

Perhaps the most recognisable impact on our terrestrial ecosystems is the disappearance of mature vegetation after fire, drought or land clearing. We should have good data on such important changes, but we don’t.

Australia is large and poorly surveyed, so national mapping relies on satellite image interpretation. We used machine-learning algorithms to update national forest maps with more recent satellite images. These updated maps estimate a nationwide increase in forest area of 510,000ha, roughly the size of Kangaroo Island.

However, this increase is the difference between much larger gains and losses. Most of the forest increases occurred in dry woodlands in NSW and Queensland, most likely due to regrowth after a relatively wet 2016.

Unfortunately, these numbers do not paint a clear picture of the state of our ecosystems. Far more is lost from removing a hectare of dense native forest than is gained from a hectare of regrowth or new planting.

The current national mapping is insufficient to make these distinctions. We now have the satellite mapping data and technologies to do a better job. This should be a priority if we are to understand how our environment is changing and meet our international commitments.

Australia’s Environment Explorer ( provides summaries of environmental condition by location or region. This example shows local government areas where vegetation cover in 2017 was above average (blue colours) or below average (red colours).

Slow changes can still be deadly

While our climate is clearly changing, it is less clear how rising temperatures are impacting on our ecosystems. Many of our species are well adapted to heat, so the effects of slowly rising temperatures may go unnoticed until it is too late.

Temperatures in excess of 42℃ can kill large numbers of flying foxes, and this happened again in 2017. We know this because they roost together in their thousands and we can count the corpses under the trees.

What heat stress does to other species is far less known. There is evidence of koalas and some large birds suffering from hot days, but we barely understand how increasing temperatures may be chipping away at the cornerstones of our ecosystems: plants, bacteria, fungi, insects and other uncharismatic creatures.

At sea, we can see the impact of high sea temperatures through coral bleaching, visible even from space. Sea surface temperatures also reached record highs off the coast of southeast Australia for the second year in a row.

On top of the steady rise of ocean temperature, sea level and acidity, the East Australian Current is strengthening and reaching ever further into the Tasman Sea. The current carries tropical reef species to Sydney and yellowtail kingfish to Tasmania. The warmer water also ravages the remaining kelp forests and stresses Tasmania’s abalone, oyster and salmon industries.

The future is already here

Last year made it abundantly clear that climate change is here now, and here to stay. We will be seeing new heat records for years to come and, sadly, some species and ecosystems are unlikely to survive the onslaught.

But there are still things we can do to limit the damage. Reducing carbon emissions will still help limit future warming. Avoiding the destruction of native ecosystems should be a no-brainer.

That isn’t just about clearing farm land, which is often singled out. Australia’s population has grown by 31% since 2000. We’re adding the equivalent of a city the size of Canberra every year.

The ConversationEach of us uses space, infrastructure and resources and produces waste at levels far above the global average. If we want our land and oceans to support our privileged lifestyle in future, we have to learn to tread more lightly, and learn it fast.

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

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

Climate policy is a fiendish problem for governments – time for an independent authority with real powers

Peter C. Doherty, The Peter Doherty Institute for Infection and Immunity

From global epidemics to global economic markets to the global climate, understanding complex systems calls for solid data and sophisticated maths. My advice to young scientists contemplating a career in research is: “If you’re good at maths, keep it up!”

I’m no mathematician – my research career has focused largely on the complexities of infection and immunity. But as recently retired Board Chair of the ARC Centre of Excellence for Climate System Science, I’ve been greatly informed by close contact with mathematically trained meteorologists, oceanographers and other researchers, who analyse the massive and growing avalanche of climate data arriving from weather stations, satellites, and remote submersibles such as Argo floats.

Read more:
Why Australians need a national environment protection agency to safeguard their health

My perception, based on a long experience of science and scientists, is that these are outstanding researchers of impeccable integrity.

Among both the climate research community and the medically oriented environmental groups such as the Climate and Health Alliance and Doctors for the Environment Australia with which I have been involved, there is increasing concern, and even fear, about the consequences of ever-climbing greenhouse gas levels in the atmosphere.

The growing climate problem

Following the thinking of the late Tony McMichael, a Canberra-based medical epidemiologist who began studying lead poisoning and then went on to become a primary author on the health section of the Intergovernmental Panel on Climate Change’s five-yearly Assessment Reports, I have come to regard human-induced global warming as similar in nature to the problem of toxic lead poisoning.

Just like heavy metal toxicity, the problems caused by atmospheric greenhouse gases are cumulative, progressive, and ultimately irreversible, at least on a meaningful human timescale.

Regrettably, this consciousness has not yet seeped through to enough members of
the Australian political class. The same lack of engagement characterises current
national politics in Russia and the United States – although some US states, particularly California are moving aggressively to develop alternative energy sources.

The latter is true for much of Western Europe, while China and South Korea are committed both to phasing out coal and to leading the world in wind and solar power technology. In collaboration with the US giant General Electric, South Korean and Japanese companies are working to develop prefabricated (and hopefully foolproof) small nuclear reactors called SMRs.

At this stage, China (currently the world’s biggest greenhouse gas emitter) is humanity’s best hope – if it indeed holds to its stated resolve.

Political paralysis

Politically, with a substantial economic position in fossil fuel extraction and
export, Australia’s federal government seems paralysed when it comes to taking meaningful climate action. We signed on to the Paris Agreement but, even if we meet the agreed reductions in emissions, precious little consideration is given to the fossil fuels that we export for others to burn. And while much of the financial sector now accepts that any new investments in coalmines will ultimately become “stranded assets”, some politicians nevertheless continue to pledge tax dollars to fund such projects.

What can be done? Clearly, because meaningful action is likely to impact both
on jobs and export income, this is an impossible equation for Australia’s elected
representatives. Might it help to give them a “backbone” in the form of a fully
independent, scientifically and economically informed statutory authority, endowed with real powers? Would such an initiative even be possible under Australian law?

Realising that reasoned scientific and moral arguments for meaningful action
on climate change are going nowhere fast, some 41 Australian environmental organisations sought the help of the Australian Panel of Experts on Environmental Law (APEEL) to develop the case for a powerful, independent Commonwealth Environmental Commission (CEC) linked to a National Environmental Protection Agency (NEPA).

This week in Canberra, at the culmination of a two-year process, the environmental groups will present their conclusions, preceded by a more mechanistic analysis from the lawyers.

In very broad terms, the new agencies would do for environmental policy what the Reserve Bank currently does for economic decisions. That is, they would have the power to make calls on crucial issues (whether they be interest rates or air pollution limits) that cannot be vetoed by the government.

Of course, that would require a government that is willing to imbue them with such power in the first place.

Read more:
Australia needs stricter rules to curb air pollution, but there’s a lot we could all do now

While it’s a good bet that developing such a major national initiative will, at best, be a long, slow and arduous process, it is true that (to quote Laozi): “A journey of a thousand miles begins with a single step”.

The ConversationWhat is also clear is that “business as usual” is not a viable option for the future economy, defence and health of Australia.

Peter C. Doherty, Laureate Professor, The Peter Doherty Institute for Infection and Immunity

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

Future tense: how the language you speak influences your willingness to take climate action

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The language that you speak may affect your approach to climate change.

Astghik Mavisakalyan, Curtin University; Clas Weber, University of Western Australia, and Yashar Tarverdi, Curtin University

Does the language we speak influence how much we care about the environment? Our new research suggests that the answer is yes.

Speakers of languages without a distinct future tense, such as Finnish, care more about the environment than speakers of languages with future tense marking, such as French or English. Their respective countries also have stricter climate change policies.

Read more:
We need to talk about how we talk about climate change

This is surprising. You might suppose that different languages are just different ways of encoding the same information. Surely when an English speaker says “It will snow tomorrow” and a German speaker says “Es schneit morgen”, they are saying exactly the same thing. Why should it matter which symbols we use?

The answer may lie in the fact that language is deeply intertwined with culture and reflects an entire way of perceiving the world, a so-called Weltanschauung (world view). This view goes back to the German Romantics, and was later popularised by the linguist Benjamin Whorf.

The Whorfian view of language was for a long time met with suspicion by linguists and cognitive scientists. But it has recently experienced a resurgence. Excitingly, it has now reached other sciences, such as economics.

Whether languages come with their own world view is an elusive question that has been the springboard for more concrete concerns from economists: does language influence tangible outcomes like saving rates or the representation of women in the labour market? Again, the answer seems to be yes.

Our research shows that the way in which a language refers to the future has a bearing on environmental behaviour and policies.

Being present

Some languages, such as Finnish or German, don’t require speakers to talk about the future in a distinct way. Rather than saying “We shall go to the movies tomorrow”, they treat tomorrow as if it were today: “We go to the movies tomorrow.”

These languages are described as “present-tensed”. (True, German is able to mark the difference with the auxiliary verb “werden”, but it isn’t obligatory and sounds artificial in everyday conversation.)

On the other side are languages, such as English or French, that do require a distinct future tense marking. These are called “future-tensed” languages.

Our research, published in the Journal of Comparative Economics, shows that speakers of present-tensed languages are more likely to engage in green behaviour.

According to our estimates, a change from a present- to a future-tensed language results in a 20% decrease in an individual’s propensity to help safeguard the environment. What’s more, speakers of future-tensed languages are 24% less willing to pay higher taxes to fund environmental policies. These estimates are based on the World Values Surveys, a collection of nationally representative, individual-level surveys conducted in nearly 100 countries.

A similar effect can be seen at the national level. Countries that speak a present-tensed language generally have stricter climate change policies.

This becomes clear by comparing countries’ scores on the CLIM index, which assesses the level of international co-operation, domestic legal frameworks, and fiscal and regulatory measures concerning climate change. The maximum score is 1, the minimum 0, and a higher value indicates stricter climate change policies.

CLIM index scores around the world.
CREDIT, Author provided

While it is true that the UK, a country with a future-tensed language, has the highest CLIM index score, other future-tensed countries (such as the United States and Australia) score 15% lower on average than present-tensed ones.

If we allow ourselves to use a hypothetical example, this suggests that if Greece were to switch from a future- to a present-tensed language, the stringency of its climate change policies would be at the level of Sweden.

What’s the explanation for this?

There are two potential mechanisms by which these effects might arise.

First, it may be that language merely reflects these societies’ underlying cultures. Put simply, some cultures care more about the future, and these cultures may also be more likely to speak a present-tensed language (which treats the future in the same way as today).

The second possibility is that language may itself influence our thinking and behaviour. Talking about the future as if it were today might make the future feel closer. Humans have a known tendency to “discount” the future – we’d rather have $100 today than in a year’s time.

So by making the future seem closer, present-tensed languages might make people care more about it. This in turn might make them more willing to bear present costs, such as higher prices for green products, for the sake of future benefits like avoiding climate change.

It’s also possible that both mechanisms work together: language might serve as a cultural marker, and at the same time shape our behaviour too. Indeed, there is evidence that this is the case.

Read more:
Thomas Piketty, climate change and discounting our future

Our results may have practical implications. In the short term, it seems unlikely that countries will eliminate the future tense from their language. But there may be other opportunities.

For instance, environmental campaigns in future-tensed countries might try to counteract the linguistic effect of future tense and portray the dangers of climate change as particularly urgent and pressing. And when deliberating about investing in otherwise similar countries, international organisations might decide that their investment has a better payoff in present-tensed countries.

The ConversationFinally, we might even suggest that international climate negotiations should be conducted exclusively in Finnish – although we might be waiting a while for everyone to catch up.

Astghik Mavisakalyan, Senior Research Fellow, Curtin University; Clas Weber, Lecturer, University of Western Australia, and Yashar Tarverdi, Research fellow, Bankwest Curtin Economics Centre, Curtin University

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

Making climate models open source makes them even more useful

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MiMA: an open source way to model the climate.
Martin Jucker, Author provided

Martin Jucker, University of Melbourne

Designing climate experiments is all but impossible in the real world. We can’t, for instance, study the effects of clouds by taking away all the clouds for a set period of time and seeing what happens.

Instead, we have to design our experiments virtually, by developing computer models. Now, a new open-source set of climate models has allowed this research to become more collaborative, efficient and reliable.

Read more:
Why scientists adjust temperature records, and how you can too

Full climate models are designed to be as close to nature as possible. They are representations of the combined knowledge of climate science and are without a doubt the best tools to understand what the future might look like.

However, many research projects focus on small parts of the climate, such as sudden wind changes, the temperature in a given region, or ocean currents. For these studies, concentrating on a small detail in a full climate model is like trying to find a needle in the haystack.

It is therefore common practice in such cases to take away the haystack by using simpler climate models. Scientists usually write these models for specific projects. A quote commonly attributed to Albert Einstein maybe best summarises the process: “Everything should be made as simple as possible, but not simpler.”

Here’s an example. In a paper from last year I looked at the temperature and wind changes in the upper atmosphere close to the Equator. I didn’t need to know what happened in the ocean, and I didn’t need any chemistry, polar ice, or even clouds in my model. So I wrote a much simpler model without these ingredients. It’s called “MiMA” (Model of an idealised Moist Atmosphere), and is freely available on the web.


The drawbacks of simpler models

Of course, using simpler models comes with its own problems.

The main issue is that researchers have to be very clear what the limits are for each model. For instance, it would be hard to study thunderstorms with a model that doesn’t reproduce clouds.

The second issue is that whereas the scientific results may be published, the code itself is typically not. Everyone has to believe that the model does indeed do what the author claims, and to trust that there are no errors in the code.

The third issue with simpler models is that anyone else trying to duplicate or build on published work would have to rebuild a similar model themselves. But given that the two models will be written by two (or more) different people, it is highly unlikely that they will be exactly the same. Also, the time the first author spends on building their model is then spent a second time by a second author, to achieve at best the same result. This is very inefficient.

Open-source climate models

To remedy some (if not all) of these issues, some colleagues and I have built a framework of climate models called Isca. Isca contains models that are easy to obtain, completely free, documented, and come with software to make installation and running easier. All changes are documented and can be reverted. Therefore, it is easy for everyone to use exactly the same models.

The time it would take for everyone to build their own version of the same model can now be used to extend the existing models. More sets of eyes on one model means that errors can be quickly identified and corrected. The time saved could also be used to build new analysis software, which can extract new information from existing simulations.

As a result, the climate models and their resulting scientific experiments become both more flexible and reliable. All of this only works because the code is publicly available and because any changes are continuously tracked and documented.

An example is my own code, MiMA, which is part of Isca. I have been amazed at the breadth of research it is used for. I wrote it to look at the tropical upper atmosphere, but others have since used it to study the life cycle of weather systems, the Indian monsoon, the effect of volcanic eruptions on climate, and so on. And that’s only one year after its first publication.

Read more:
Climate models too complicated? Here’s one that everyone can use

Making models openly available in this way has another advantage. Using an accessible proof can counter the mistrust of climate science that is still prevalent in some quarters.

The burden of proof automatically falls on the sceptics. As all the code is there and all changes are trackable, it is up to them to point out errors. And if someone does find an error, even better! Correcting it is just another step to make the models even more reliable.

The ConversationGoing open source with scientific code has many more benefits than drawbacks. It allows collaboration between people who don’t even know one another. And, most importantly, it will make our climate models more flexible, more reliable and generally more useful.

Martin Jucker, Maritime Continent Research Fellow, University of Melbourne

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