22 April 2013

Another day in paradise

COSMOS Magazine
Can we predict the future? Climate scientists say we can, and have been warning us about it for decades, says Stephen Pincock.
2063 climate (pt 2)

PALE GREY CLOUDS drift across the sky and a cool breeze tousles the waters of Sandy Bay in Hobart, Tasmania. At the start of what promises to be a gruelling week, climate scientists crowd around a conference centre foyer, taking in the view.

It’s early January 2013, and these experts from across the globe have come to Australia’s southerly island state for a meeting of the Intergovernmental Panel on Climate Change (IPCC). Hobart’s weather generally tends toward mild and damp; cold winds from Antarctica regularly bring snow to the rocky peak of nearby Mount Wellington. Over the past century or so, the city’s average January maximum has been just 21°C.

Yet, during the previous week, Hobart had experienced its hottest day on record, with the temperature soaring above 40°C. Instead of clouds, the sky was wreathed in smoke. In the nearby fishing village of Dunalley, 80 homes, some 30% of the town, were destroyed by bushfires. Hundreds of residents were evacuated by boat from the Tasman Peninsula.

The scientists are here to help finalise sections of the IPCC’s latest and massively complex assessment report, the fifth such mammoth document released over the past 25 years. Part of their job is to outline the range of possible future climates humanity can expect over the coming decades.

A few weeks earlier, a draft version of the report was leaked on a blog by a climate sceptic who was also one of the experts engaged in the review process. The report is due to be released in three stages, beginning in September 2013, and wording may change. As it is, the draft suggests that 50 years from now, average surface air temperatures could be between 1°C and 2°C warmer than they were in the early 2000s. This is on top of a warming of about 0.8°C already recorded since the Industrial Revolution.

Other organisations have released more worrying forecasts. In November 2012, a report for the World Bank compiled by the Potsdam Institute for Climate Impact Research in Germany warned that, if governments fail to meet current mitigation pledges and commitments, the average global temperature could rise 4°C above pre-industrial temperatures by as early as the 2060s. In line with the IPCC, most of the experts I spoke with for this story said while this kind of hike was possible, by mid century, rises of the order of 1°C or 2°C were more likely, with further increases to follow.

Even this kind of rise approaches a level of warming that governments agree would risk dangerous anthropogenic interference with the climate system. During a coffee break at the Hobart meeting I chatted with Andy Pitman, a climate modeller who directs the ARC Centre for Climate System Science at the University of New South Wales (UNSW) in Sydney. A straight-talking man, he’s more than a little exasperated as he explains that much of the fundamental understanding of climate science is settled.

“There is zero disagreement over whether the Earth will warm if we continue to put nine billion tonnes of carbon dioxide into the atmosphere each year,” he says. “That’s just not up for discussion, which is why we find the debates with the sceptics so tedious. It’s like arguing the toss over whether the average car has four wheels or not.”

As the scientists begin filing back into their meeting rooms, I ask Pitman how likely we are to stay under the 2°C limit this century. “We’ve got,” he answers quickly, “a snowball’s chance in hell”.

A WEEK AFTER THE meeting, I arrange to meet Pitman for a longer talk. He makes me coffee and ushers me into the sort of office that could easily belong to a historian or psychiatrist. Pitman’s experiments take place not in a lab but amid millions of lines of computer code. He uses elaborate climate models to help pose the question: what is our climate future? Based on fundamental laws of physics, these models work at grid-level scales, using a 3-D array of ‘cells’ of regional zones to artificially generate all the complexities of a climate system: the swirling clouds and flooding rivers, dynamic oceans and polar ice caps. These cells and all their variables – including data on the rate of change of temperature, humidity, and the flow of energy in and out of the system – are enmeshed in mathematical relationships played out in supercomputers.

I ask him how these models work on a practical level. “We take the Earth as a sphere, and break it up into a chessboard pattern, and up into multiple levels – like the 3-D chessboard Spock plays on in Star Trek,” he explains. The model maps the climate now and mathematically predicts the next step of progress – perhaps just half an hour later – to see how the whole system changes. The model then solves the equations again for the next half hour – and so on, for however long he wants it to run. Just one of these simulations might take six to nine months in real time, and the output is a mathematical representation of the entire globe, inscribed in perhaps a million gigabytes of data.

Scientific groups around the world operate different versions of these virtual worlds. When several of their models agree, scientists can state with what level of confidence – statistically speaking – they can be sure their model is correct in its predictions. Where more models agree, there’s more certainty.

Among the most certain repercussions of a warming climate is that extremely hot days will become more frequent. So when the Tasmanian emergency services minister reassured Hobart residents that the bushfires of 2013 were the result of catastrophic weather conditions that occur “once in a generation”, he was making an assertion that may not still be true 50 years from now.

In climate terms, 50 years isn’t that far into the future. Chris Field, founding director of the Department of Global Ecology at the Carnegie Institution for Science in California, says much of the change we can expect over the next five decades is already in train.

“We’re looking now at consequences of things that have already been baked into the system, consequences of emissions that have already occurred,” he says. “Even if we started tomorrow with aggressive emissions reductions, it would only mean a few per cent difference the first year and a few more for the second year and so on.” Some of the consequences of today’s emissions won’t even have kicked in by mid century, he adds.

IN THE MIDDLE OF a hot spell in Sydney in the southern summer, when temperatures in the mid 40s have forced many folks into shopping malls and cinemas for relief, I call Lisa Alexander, an expert in extreme weather events at the Climate Change Research Centre at the UNSW, to discuss what ramifications global warming could have over the next 50 years.

“What we consider today to be an extreme of temperature, that’s going to become the norm by the middle of the century,” she says. “The sort of temperatures we’ve had in Sydney this week, rather than happening once in a summer, will start to occur a lot more often.”

In November 2011, consultancy firm PricewaterhouseCoopers Australia compiled a report for the Australian Government, looking specifically at the question of extreme events. “By 2050, an extreme heat event in Melbourne alone could typically kill over one thousand people in a few days if we don’t improve the way we forecast, prepare for and manage these events,” it warned. For Victorian residents who lived through the ‘Black Saturday’ fires in 2009, when drought and temperatures over 45°C led to 173 people dying in bushfires, these are alarming words.

It’s not only Australia that will see these kinds of extreme events more often. By the middle of the century, extreme highs will become more common across the globe, according to a special report released by the IPCC in March 2012. Temperatures historically hit once every 20 years could become 10 times more common in some places. Nearly everywhere on the planet will be hit by heatwaves, says Alexander. Europeans learned the impact such events could have in 2003, when an estimated 70,000 people died during the hottest summer on record since 1540.

AS THE TEMPERATURE rises, it will disrupt patterns of rainfall and snowfall, making heavy downfalls more common on a global scale. Trying to predict what will happen to rainfall at a regional level in the next 50 years is harder. “Broadly, we could say the wet places will get wetter and the dry places will get drier,” Alexander says. “But there are quite a few places where we’re not getting the majority of models agreeing on what will happen in individual regions.” Other areas could change from wet to dry, or vice versa, she says.

In China, for example, “data indicate that some of the traditionally dry areas will actually become slightly wetter, and in some of the relatively wet areas, the precipitation will be reduced,” says Yiqi Luo, co-director of the Fudan Tyndall Centre for Climate Change Research in Shanghai.

Heavy downpours could mean an increased risk of flooding in some areas, perhaps similar to the floods that turned three quarters of the Australian state of Queensland into a disaster zone in 2010. On the other hand, changing rainfall patterns could also lead to an increased risk of drought. The climate change report for the World Bank estimated that a 2°C increase in global average temperatures could cut annual runoff by 20% to 40% in vital river basins such as the Amazon, the Mississippi and the Murray–Darling, while increasing runoff by around 20% in the Nile and the Ganges.

Perhaps unsurprisingly, changes in rainfall patterns and temperatures will also have an impact on the risk of forest fires by 2063, scientists say. In Amazonia, for example, the World Bank report estimates that forest fires could as much as double by 2050 with warming of approximately 1.5°C to 2°C above pre-industrial levels.

Meanwhile, rising temperatures are also expected to raise sea levels, by melting glaciers and polar ice caps and causing ocean water to expand. The oceans have an enormous capacity to absorb the warming caused by rising greenhouse gas concentrations in the atmosphere, and the rise in sea levels is expected to happen slowly, explains John Church, a lead IPCC author from Australia’s national research agency CSIRO. “By 2063, there would be a growing but at this time relatively small impact on sea level change,” he says. He estimates a rise of about 20 to 50 cm from the sea level in 2000.

It’s long been postulated that climate change will also cause more severe storms. “It’s really the intensity of the cyclone that’s the problem, rather than the frequency,” says Alexander. “If you get low-category cyclones, they’re much less of a problem than if you get the large, intense cyclones.”

The costs of such an increase could be enormous. In 2012, the costliest natural catastrophe for the U.S. insurance industry was Hurricane Sandy, which caused overall losses that giant insurer Munich Re put at US$50 billion including in excess of US$25 billion in insured losses. And as Munich Re pointed out in January 2013, recent years have already seen a “strong upward trend in insured losses” related to thunderstorms in the USA.

Yet the cost of Hurricane Sandy could pale in comparison to the trillions of dollars required for coastal defences to protect cities from rising sea levels. “If there is half a metre of sea level rise, followed by 1 m, then, for sure, most of China’s major cities along the coast regions will be affected,” says Luo. “In China, 80% of people live in relatively low elevation areas in coastal regions.”

FOR ALMOST TWO DECADES, Nick Rowley has had a ringside seat to the bruising politics of climate change. In recent years, the British policy consultant has advised companies and governments on sustainability. Before that, he was a climate advisor to New South Wales premier Bob Carr, then British Prime Minister Tony Blair.

Over that time, Rowley says, he has watched climate experts become resigned to the inevitability of dangerous climate change. “When I was working with Tony Blair seven years ago, there was a level of energy and focus among scientists, advocates and policy professionals addressing the problem.”

Today, that enthusiasm and motivation has been lost, he says. “Their tone is one of accepting that this world is going to change fundamentally over the coming 50 years because of the climate problem.”

Rowley is far from alone in that dismal assessment. David Karoly, a senior climate change researcher at the University of Melbourne, worries that meaningful political action will come about only when the gradual accumulation of disaster upon disaster – floods on fires on ‘Frankenstorms’ – make it impossible for the status quo to continue.

“For there to be a switch from political inaction to political action, there will have to be some very, very major climate-related disasters,” he says. “Many people will call those cataclysmic.” Karoly’s guess is that political change will start happening around 15 years from now. “But my view is that emissions won’t start to fall until 2050.”

An important part of that delay is the economic commitments countries are making right now to build coal-fired power stations. “It’s a kind of inertia that’s really important for the global economy,” says Field. “If we have to start retiring power plants that are only half their retirement age, or 10% of their retirement age, then we’re imposing both the early retirement costs and the extra costs of the renewables. And that’s when it starts getting really expensive.”

IN THIS VERSION OF 2063’s climate, “survival and adaptation would be the name of the game”, says Hans Joachim Schellnhuber, founding director of the Potsdam Institute for Climate Impact Research in Germany. “It would be a world on the edge of despair… but people would still feel they can adapt. A world that would be manageable, but there would still be heavy losses.”

Adaptation would be one priority: adjusting the way we organise our lives, cities and industries to cope with the changed conditions. Another would be fighting to minimise more disruptive change. By 2063, simply cutting emissions may not be enough to achieve this. Indeed, by the middle of the century the world may well have already dabbled with various technological fixes to try to cool the Earth and strip carbon dioxide out of the atmosphere.

“I think the key point is that we will face continuing impacts and will face even worse impacts after we’ve realised that the problem needs to be solved,” says Field. There are profound issues with the gamut of geoengineering concepts aiming to mitigate climate change, he says. “If we want to know how well any of those things are going to work, and especially how well they are going to scale, we should be studying them real hard, right now.”

The kind of radical schemes that can garner headlines – shielding the Earth from sunlight with giant mirrors in space, or with reflective aerosols in the upper atmosphere – may have been tested at smaller scales, but most have failed or been banned because they are too expensive or risky, says Schellnhuber. “Solar radiation management is dangerous nonsense.”

Field, Schellnhuber, Karoly and others are more optimistic that over the next 50 years we will get better at capturing carbon dioxide emissions from power stations, or from the atmosphere itself. Some of the most promising approaches are a return to natural mechanisms, says Schellnhuber. “I would say the natural method of geoengineering would be best: planting trees.” Maintenance of tropical forests and bans on land clearing would also help reduce the atmospheric concentration of carbon dioxide.

Others think these natural approaches will not be enough and that new technologies will also be needed, some of which may already be on the horizon. In Queensland, for example, a pilot scheme by Australian energy company MBD Energy uses algae to capture carbon dioxide emissions from a power station in the town of Tarong, northwest of Brisbane, and grow feedstock. And in July 2012, global tech company Panasonic said it had developed a relatively efficient artificial photosynthesis system to convert carbon dioxide into fuels.

Fifty years from now, humanity is bound to have tools at its disposal that are just as unimaginable as smartphones and the Internet were in 1963. In predicting the future of climate change, “I think one of the weaknesses we often see is an expectation that in 50 years people are going to be using the same technology we have now,” says Field. “It’s interesting, when you look at 1963, some things have not really changed at all… but other things have changed drastically.”

IF THE CLIMATE OF 2063 does change substantially, it is unlikely to yet be enough to threaten civilisation, or usher in widespread ecosystem destruction. It is likely, however, that both temperatures and carbon dioxide concentrations will keep rising for another 50 years or more. “We could go to a 3°C increase over current levels by 2100,” says Schellnhuber.

By this time, seas could be a metre higher than they were before the industrial revolution, says Karoly. By 2150, a 2 m rise is possible. If this comes to pass, hundreds of millions of people could be displaced.

The scientists I spoke with worry that the citizens of 2063 will rue our failure to act on climate change today. “Sadly, in 2063 people are likely to look back at this generation and be damning of it,” says Rowley. “They will say that on the basis of the evidence presented to you, by the very best minds who have devoted their lives to understanding this complexity, you as societies were not willing to make the decisions and implement the policies to reduce the climate risks and costs that we now endure.”

After a couple of hours chatting with Pitman, our conversation takes a turn in the same direction. In 2063, he points out, it will be our children and grandchildren left to deal with the consequences of climate change. “I think they will look back and curse the current generation of political leaders. One of the cruel realities is that every one of those leaders will be dead, and not be held accountable.”

Stephen Pincock is a science journalist, editor and author and a regular COSMOS contributor.

2063 special: climate change

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