Tuesday, January 11, 2011

Fates conspire to concoct a recipe for disaster

Bridie Smith 
The Age, January 12, 2011
THE strong La Nina pattern currently transporting moisture to north-eastern Australia has been exaggerated further by record-high ocean temperatures - a combination not seen on this scale since the deadly Brisbane flood of 1974, which claimed at least 14 lives.
And while Queensland's already saturated catchments are lashed with heavy rain, the south-west of Western Australia is experiencing an extreme dry - and bushfires.
''Australia has been known for more than a hundred years as a land of droughts and flooding rains, but what climate change means is Australia becomes a land of more droughts and worse flooding rains,'' said David Karoly from Melbourne University's school of earth sciences.
Professor Karoly stressed individual events could not be attributed to climate change. However, he said the wild extremes being experienced on the continent were in keeping with scientists' forecasts of more flooding associated with increased heavy rain events and more droughts as a result of high temperatures and more evaporation.
''On some measures, it's the strongest La Nina in recorded history … [but] we also have record-high ocean temperatures in northern Australia, which means more moisture evaporating into the air,'' he said. ''And that means lots of heavy rain.''
In Queensland's case, the recent rain fell on already saturated catchments, which had been soaked by heavy rains, making the run-off rate high.
In the weeks from November 28 to December 31, total rainfall exceeded 300 millimetres over most of the eastern half of the Sunshine State. ''In Victoria, while we had heavy rainfall, the run-off hasn't been as high because after 10 years of drought, the ground wasn't as saturated,'' he said.
A Bureau of Meteorology special climate statement issued this week said last month was the wettest December on record for Queensland and for eastern Australia as a whole. This followed an unusually wet Australian spring - the wettest on record for Queensland and NSW.
A visiting fellow at the Australian National University's integrated catchment assessment and management centre, Tony Weber, said the catchments had reached saturation levels and there didn't need to be record rainfalls to result in ''extreme run-off events''. He said it would take several weeks before the catchments were sufficiently dry to lift the threat of further flooding - and even then, that would only occur if significant rainfall eased.
La Nina phases recur every three to five years, lasting about 12 months. Professor Karoly said the current cycle began earlier than usual and could last until May. The last La Nina event was in 2007.

Monday, January 10, 2011

Warming to devastate glaciers, icesheet: report

ABC News Online, 10 January 2011

Global warming may wipe out three-quarters of Europe's alpine glaciers by 2100 and hike sea levels by four metres by 3000 through melting the West Antarctic icesheet, two studies published at the weekend said.
The research places the spotlight on two of the least understood aspects of climate change: how, when and where warming will affect glaciers on which many millions depend for their water and the problems faced by generations in the far distant future.
The glacier study predicts mountain glaciers and icecaps will shrink by 15 to 27 per cent in volume terms on average by 2100.
"Ice loss on such a scale may have substantial impacts on regional hydrology and water availability," it warns.
Some regions will be far worse hit than others because of the altitude of their glaciers, the nature of the terrain and their susceptibility to localised warming.
New Zealand could lose 72 per cent of its glaciers and Europe's Alps 75 per cent.
At the other end of the scale, glacial loss in Greenland is predicted at around 8 per cent and at some 10 per cent in high-mountain Asia.
Meltwater will drive up world sea levels by an average of 12 centimetres by 2100, the study says.
This figure - which does not include expansion by the oceans as they warm - largely tallies with an estimate in the Fourth Assessment Report by the UN's Intergovernmental Panel on Climate Change (IPCC) in 2007.
Geophysicists Valentina Radic and Regine Hock of the University of Alaska base these calculations on a computer model derived from records for more than 300 glaciers between 1961 and 2004.
The model factors in the middle-of-the-road "A1B" scenario for greenhouse-gas emissions, by which Earth's mean surface temperature would rise by 2.8 degrees Celsius during this century.
The tool was then applied to 19 regions that contain all the world's glaciers and icecaps.
But it does not include the icesheets of Antarctica and Greenland, where 99 per cent of Earth's fresh water is locked up.

'Widespread collapse

If either of these icesheets were to melt significantly, sea levels could rise by an order of metres, drowning coastal cities.
That scenario emerges in the second study, which focuses on the inertial effect of greenhouse gases. Carbon molecules emitted by fossil fuels and deforestation linger for many centuries in the atmosphere before breaking apart.
Even if all these emissions were stopped by 2100, the warming machine would continue to function for centuries to come, says the investigation.
It largely bases its forecast on the "A2" emissions scenario, which sees greater carbon pollution by 2100, stoking Earth's temperature by an average 3.4 C (6.1 F) by century's end.
Warming of the middle depths of the Southern Ocean could unleash the "widespread collapse" of the West Antarctic icesheet by the year 3000, it says.
"The inertia in intermediate and deep ocean currents driving into the southern Atlantic means those oceans are only now beginning to warm as a result of CO2 (carbon dioxide) emissions from the last century," said Shawn Marshall, a professor the University of Calgary in Canada.
"The simulation showed that warming will continue, rather than stop or reverse, on the thousand-year timescale."
The two studies are published online by the journal Nature Geoscience (here and here).
- AFP

Saturday, January 8, 2011

Warm Arctic, lowest sea ice extent

NSIDC Arctic News and Analysis, January 5, 2011

Repeat of a negative Arctic Oscillation leads to warm Arctic, low sea ice extent

Arctic sea ice extent for December 2010 was the lowest in the satellite record for that month. These low ice conditions are linked to a strong negative phase of the Arctic Oscillation, similar to the situation that dominated the winter of 2009-2010.

Overview of conditions

Arctic sea ice extent averaged over December 2010 was 12.00 million square kilometers (4.63 million square miles). This is the lowest December ice extent recorded in satellite observations from 1979 to 2010, 270,000 square kilometers (104,000 square miles) below the previous record low of 12.27 million square kilometers (4.74 million square miles) set in 2006 and 1.35 million square kilometers (521,000 square miles) below the 1979 to 2000 average.

As in November, ice extent in December 2010 was unusually low in both the Atlantic and Pacific sides of the Arctic, but particularly in Hudson Bay, Hudson Strait (between southern Baffin Island and Labrador), and in Davis Strait (between Baffin Island and Greenland). Normally, these areas are completely frozen over by late November. In the middle of December, ice extent stopped increasing for about a week, an unusual but not unique event.

Conditions in context

The low ice conditions in December occurred in conjunction with above-average air temperatures in regions where ice would normally expand at this time of year. Air temperatures over eastern Siberia were 6 to 10 degrees Celsius (11 to 18 degrees Fahrenheit) above normal in December. Over the eastern Canadian Arctic Archipelago, Baffin Bay/Davis Strait and Hudson Bay, temperatures were at least 6 degrees Celsius (11 degrees Fahrenheit) higher than average. Southern Baffin Island had the largest anomalies, with temperatures over 10 degrees Celsius (18 degrees Fahrenheit) higher than normal. By sharp contrast, temperatures were lower than average (4 to 7 degrees Celsius, 7 to 13 degrees Fahrenheit) over the Alaska-Yukon border, north-central Eurasia, and Scandinavia.

The warm temperatures in December came from two sources: unfrozen areas of the ocean continued to release heat to the atmosphere, and an unusual circulation pattern brought warm air into the Arctic from the south. Although the air temperatures were still below freezing on average, the additional ocean and atmospheric heat slowed ice growth.

Last chance to hold Greenland back from tipping point

05 January 2011 by Anil Ananthaswamy 

New data and models show that Greenland's ice cap, the world's second largest, is on track to hit a point of no return in 2040

ON 4 AUGUST 2010, the Petermann glacier in Greenland sounded a warning. A gigantic slab of ice broke off and the glacier retreated 15 kilometres, leaving it further inland than it has been since observations began a century ago.

That warning went unheeded at the UN climate talks in CancĂșn, Mexico, last month. Delegates left without agreeing drastic cuts in greenhouse gas emissions, leaving the planet on course for 3.2 °C of global warming, and Greenland - the world's second largest ice cap - heading for a point of no return. The suggestion is that Greenland will reach a tipping point in the early 2040s. After that no amount of action on our part can save the ice sheet. Unless governments dramatically up their game, the only thing that will change that date is natural variations in the climate, which might either hasten or delay the tipping point.

Greenland's ice sheet holds enough ice to raise global sea levels by 7 metres. Ice melting at the surface and breaking off at the margins of the ice sheet is already adding up to about 300 gigatonnes each year. That accounts for about 25 per cent of the annual, global rise in sea levels.

Last month's meeting of the American Geophysical Union in San Francisco highlighted the situation. Jason Box of Ohio State University in Columbus and colleagues listed Greenland's "biggest losers": the five glaciers and ice streams that lost the greatest area of ice in the past decade. The Petermann glacier topped the chart, with 500 square kilometres (see map).

But not all ice is created equal. Glaciers in the north like Petermann and Humboldt lost a lot of thin, floating ice that does not impede the outward flow of ice behind. That means the glaciers did not immediately surge seaward. But thicker ice was exposed to the ocean. Thicker ice acts like a cork in a bottle: take it away and the glaciers accelerate. "If we continue to lose ice, we'll start losing important ice," says team member Ian Howat, also at Ohio State University. "If these glaciers were to accelerate and mobilise the large amount of ice up in northern Greenland, it has the potential for a huge change."

It is the kind of change that has already been seen in Greenland, south of 70 degrees latitude. For instance, the speed at which the Jakobshavn glacierflows has more than doubled over the past 10 years. In July, its margin withdrew by about 1.5 kilometres, bringing its grounding line - where the glacier lifts off the bedrock and begins floating - to a knife edge, where bits can break off to form icebergs.

Beneath the ice, Greenland is built like a soup dish: the bedrock slopes down towards the interior and in the case of Jakobshavn bottoms out some 1600 metres below sea level. Jakobshavn's margin is now perched on the edge of that dish. If it breaks up further, it would end up on a downward slope, with nothing to stop it slipping 80 kilometres inland.

"It would cause a huge embayment into the ice sheet, something that we have never seen before," says Howat. Jakobshavn is one of many glaciers perched on similar topography. "Once a glacier hits this point, the dynamics of the ice take over. No matter what climate does, whether it gets warmer or colder, that glacier is going to keep [retreating]," says Howat.

One-way ticket

Other factors could also put glaciers on a one-way ticket to extinction. Kristin Poinar of the University of Washington, Seattle, and colleagues have been studying the bottom of Jakobshavn. The ice there is slushy due to the enormous friction and pressure at those depths: friction within the glacier and against the bedrock generates enormous amounts of heat. Studies show this "temperate ice" layer is about 270 metres thick and acts like a conveyor belt, helping the ice slip faster into the sea.

Not only that, it could give glaciers some form of "memory" of past warm events, says Poinar.In the 1990s, warm ocean waters caused Jakobshavn to speed up dramatically, creating more temperate ice, which could stick around for decades. That means the consequences of sudden changes like Jakobshavn's increase in speed in the 1990s could be felt for tens or hundreds of years, says Poinar.

Thousands of smaller glaciers are also showing dramatic declines. Sebastian Mernild of the Los Alamos National Laboratory in New Mexico and colleagues have been studying one in south-east Greenland, close to the Sermilik fjord. From photographs going back to 1931, the team calculated that the glacier has retreated by 17 metres per year on average, but in 2010 it lost ground by 35 metres. "The same trend is happening to all the glaciers in east Greenland," says Mernild.

Last year was also a bad one for the ice sheet as a whole. By combining observations and modelling, Mernild's team calculated that 52 per cent of the ice sheet experienced surface melting. Natural annual variability can't be ruled out, says Mernild, "but if you check the trends, surface melt has been increasing since 1972, all the way up to 2010, and 2010 was a record year". South-west Greenland saw a dramatic increase in the number of melting days, about 50 days more than the average for the past 50 years. And three decades of measurements from the Watson river drainage basin in west Greenland show that surface runoff in 2010 was 30 to 40 per cent higher than average (Cryosphere, DOI: 10.5194/tc-4-231-2010).

More melting is in store, warns Mernild. His team's models show that Greenland's glaciers haven't fully responded to the temperature rises. In other parts of the world, including Antarctica and the Himalayas, glaciers are about 25 per cent out of equilibrium, meaning that even if warming were to stop today, the glaciers would continue to melt further before stopping. But temperatures in and around Greenland have been increasing faster than elsewhere, and the glaciers there are 70 per cent out of equilibrium, says Mernild.

This worries Mernild. His team modelled the fate of Greenland, using a scenario for future human development outlined by the Intergovernmental Panel on Climate Change. The scenario assumes rapid economic growth, a global population that peaks in 2050, and rapid adoption of new, efficient technologies for energy use and generation. Given the outcome in CancĂșn last month, it is a likely scenario for the future.

Mernild's models show that if it does play out, Greenland will reach a tipping point in about 30 years. After that nothing will prevent the ice cap from eventually vanishing entirely (Journal of Hydrometeorology, DOI: 10.1175/2009JHM1140.1).

"We can see which way the trend is going," says Mernild. "It doesn't look nice".

Tuesday, January 4, 2011

Annual Australian Climate Statement 2010

Bureau of Meteorology

Issued 5th January 2011
2010 La Niña event brings Australia's third-wettest year on record.
  • La Niña brings heavy rain, eases drought and causes widespread flooding
  • Prolonged dry conditions continue in southwest Western Australia
  • Australia's coolest year since 2001
  • Australia's warmest 10 years on record

Overview

Data collected by the Bureau of Meteorology show that the Australian mean rainfall total for 2010 was 690 mm, well above the long-term average of 465 mm. As a result, 2010 was Australia's wettest year since 2000 and the third-wettest year on record (records commence in 1900). The only month to record a national monthly total below the long term average during 2010 was June. This means that 11 months of the year experienced above average rainfall, an occurrence observed only once previously, in 1973.
2010 began with El Niño conditions in the Pacific followed by a rapid transition into La Niña during autumn. From January to May rainfall was generally above average in most areas except the western half of Western Australia and southern Tasmania. By July, La Niña conditions were well established and most areas of Australia experienced very much above average rainfall. The second half of the year (July to December) was the wettest on record for Australia.
However, not all areas were very wet during 2010. Southwest Western Australia had its driest year on record, and Tasmania had near to average rainfall for the year; the result of a dry first six months followed by a relatively wet second six months.
Mean temperatures in 2010 were cooler than those for the previous eight years, with an average of 22.0°C, +0.19 °C above the 1961 to 1990[1] average of 21.81 °C. Despite 2010 being cooler than recent years, the decade ending 2010 is now the hottest decade on record for Australia with an anomaly of +0.52 °C. This underscores that the warming of Australia's climate continues, even though individual years may be cooler than other years.

Very wet through the north and east

Rainfall was above average across most of the country, with record rainfall reported in many areas. Unusually heavy falls were experienced in Queensland, New South Wales, the Northern Territory and South Australia. Based on preliminary numbers, 2010 was the wettest year on record for Queensland. The Northern Territory, New South Wales and South Australia experienced their 3rd wettest year on record, and Victoria experienced its 5th wettest year on record.

Drought eases in the east but continues in the southwest

For some parts of the southeast 2010 was the first calendar year since 1996 to see above average rainfall. The heavy rainfall in 2010 marked a dramatic reversal of dry conditions across Queensland, New South Wales, Victoria and South Australia. Significantly, the Murray Darling Basin recorded its wettest year on record, ending a record sequence of below average rainfall years extending back to 2001. This rainfall led to a dramatic recovery in water storages across the Murray-Darling Darling Basin from 26% at the start of 2010 to 80% at the start of 2011.
From the point of view of surface water, soil moisture and annual rainfall totals; the "long dry" which commenced in late 1996 in the far southeast of mainland Australia and late 2001 across much of the Murray-Darling Basin has effectively ended.
In contrast to the rest of the continent, the southwest of Western Australia experienced a very dry year, continuing the long drying trend which extends back to the late 1960s. For the southwest region as a whole, the 2010 rainfall total was a record low 392 mm, well below the previous low of 439 mmin 1940. Rainfall in the cropping season (April to October) in southwest Western Australia also set a record with just 310 mm falling; the previous low was 348 mm in 1914.

Wettest on record "dry season" in the north

For the period from May to October, considered to be northern Australia's dry season, conditions were abnormally wet. Northern Australia had its wettest dry season on record, measuring an average of190 mm of rainfall, compared with the previous record of 176 mm in 1978. June was the only month to see the widespread dry conditions that are typical of the season. September was a particularly notable month for rainfall, coming in as the wettest on record for northern Australia with an average of 51 mm, well above the previous record of 33 mm set in 1906.

Big wet results in coolest year since 2001 but nonetheless the warmest decade on record

Overall, Australia's annual mean temperature for 2010 was 22.00 °C, +0.19 °C above the 1961 to 1990 average of 21.81 °C. This ranks as the nation's 31st-warmest year since standard records began in 1910. It has now been a record nine years since Australia experienced a below-average year and the past ten years (2001 to 2010) were the warmest decade on record for Australia.
Temperatures were generally cooler than average in the interior of the continent where rainfall was particularly high. By contrast, the north and west were much warmer than normal. Warmer than normal sea surface temperatures in the Coral Sea contributed to the warm temperatures in the Cape York Peninsula. Tasmania was also warmer than normal.
Australia recorded its 8th warmest year on record for minimum temperatures (with an anomaly of+0.59 °C), while maximum temperatures were below normal with an anomaly of −0.21 °C. The tropics were particularly warm during the July to October period, with widespread areas in the Top End of the Northern Territory, the Gulf of Carpentaria and the Cape York Peninsula having their warmest on record mean temperatures. In marked contrast with 2009, days with extreme high temperatures were scarce. However 2010 saw regular, very high overnight minimum temperatures in the northern tropics during winter, including an Australian July record of 26.9 °C at Cape Don in the Northern Territory.

Flooding and storms

As can occur during significant La Niña events, there were numerous significant floods in Australia during 2010, especially in the eastern states. The most widespread and damaging floods of the year occurred across Queensland in the final week of 2010 (and continuing into early 2011). Floodwaters were fed by heavy rain over the Christmas period falling over areas already saturated by persistent above-average rainfall during the preceding months. The most severe impacts were in central Queensland and in the state's southern inland regions. Thousands of properties were inundated in Emerald, Bundaberg, Rockhampton and many smaller centres, while the communities of Theodore and Condamine were evacuated. Numerous rivers throughout the region reached record levels. Damage to property and infrastructure, as well as the economic cost from crop losses and disruptions to mining, is expected to run to several billion dollars.
An earlier major flood event in late February and early March affected central Australia, Queensland and far northern New South Wales. A monsoon low located over the Northern Territory moved southwards and then eastwards into southern Queensland, and then into northern New South Wales. This system produced heavy rainfall in its path resulting in widespread flooding. Major flooding occurred in most of the catchments in southern inland Queensland, and some of these areas had their highest flood levels on record. This event also brought minor flooding to the southern Northern Territory, and as the Queensland waters moved downstream, significant flooding occurred in northwest New South Wales, with some areas remaining affected by floodwaters well into April. It also combined with earlier regular rains in inland Queensland to contribute to a significant filling of Lake Eyre.
Many other floods occurred during the year. Significant flooding occurred across inland New South Wales in December, particularly in the Murrumbidgee Catchment around Queanbeyan and Wagga Wagga, and the Lachlan Catchment around Eugowra (which was flooded three times during the month). Major floods also occurred in northern Victoria and the New South Wales Riverina region in early September; and the Gascoyne River around and upstream of Carnarvon in mid-December.
Two significant and highly damaging thunderstorm events producing large hailstones occurred during March 2010, with losses from each event estimated by the Insurance Council of Australia to exceed $1 billion. The first occurred in Melbourne on 6 March, with the heaviest falls coming in less than 30 minutes, resulting in flash flooding in the inner city. Hail up to 5 cm in diameter fell across a large swathe of Melbourne with widespread damage to cars and houses. A 10 cm hailstone was measured in the suburb of Ferntree Gully, in Melbourne's east, twice the diameter of the previous largest stone on record for Melbourne.
The second thunderstorm event occurred in Perth on the afternoon of 22 March. This thunderstorm produced heavy rain, severe winds and the largest hail stones on record for Perth. The largest hail from this storm occurred in the northwestern suburb of Wembley, where a 6 cm hailstone was reported.

Sea surface temperatures near Australia

Based on preliminary data (to November 30), sea surface temperatures in the Australian region during 2010 were +0.54 °C above the 1961 to 1990 average. This is the warmest value on record for the Australian region. Individual high monthly sea surface temperature records were also set during 2010 in March, April, June, September, October and November. Along with favourable hemispheric circulation associated with the 2010 La Niña, very warm sea surface temperatures contributed to the record rainfall and very high humidity across eastern Australia during winter and spring. The most recent decade (2001−2010) was also the warmest decade on record for sea surface temperatures following the pattern observed over land.

Globally 2010 is likely to be one of the warmest years on record

The past year has been very warm globally, though it remains too early to determine if the year will be the warmest or second warmest on record.
On 3 December the World Meteorological Organization (WMO) declared that year 2010 is almost certain to rank in the top three warmest years since the beginning of instrumental climate records in 1850. The global combined sea surface and land surface air temperature for 2010 (January−October) is currently estimated at +0.55 °C ± 0.11 °C above the 1961 to 1990 annual average of 14.0 °C.
A cooler-than-average global mean temperature has not been recorded since 1985 (for the last 25 years). The past 10 years have been the globe's hottest on record with an anomaly of +0.46 °C. Increasing global mean temperatures derived from instrumental measurements are consistent with other independent indicators of climate change, such as reductions in ice and snow cover, and rises in global sea levels.

Accessing Australia's climate change datasets

The Bureau of Meteorology is responsible for collecting, managing and safeguarding Australia's climate archive. Several high-quality datasets have been developed from this archive to identify, monitor and attribute changes in the Australian climate. Extensive rehabilitation work has been undertaken on these data to ensure they have not been compromised by changes in site location, urbanisation, exposure or instrumentation over time. The high-quality data can be accessed at:http://www.bom.gov.au/climate/change/hqsites/
Please note that heavy rainfall over the Christmas-New Year period, with severe flooding in Queensland, has affected the availability of rainfall data for northeast Australia. As these data are processed in the next few months the final rainfall figures are expected to change.

Saturday, January 1, 2011

The deadly decade

Adam Morton 
The Age, December 31, 2010
The past 10 years have been the hottest since measurements began, and climate scientists have long warned of the extreme weather still to come. Adam Morton reports.
Neville Nicholls is a climate scientist. He has long believed his role was research, not advocacy. But when he woke on the morning following Black Saturday, turned on his TV and caught his breath after witnessing the shocking aerial footage of what was once Marysville, he instinctively blamed himself.
"My initial thought was: is this my fault? Has this happened because I haven't been out there saying that this stuff is going to have catastrophic consequences for us?" he recalls. "It is the first time I have ever been shaken from my belief that I shouldn't be an advocate on climate change."
Nicholls — an Australian Research Council professorial fellow at Monash University and an author and reviewer with the United Nations Intergovernmental Panel on Climate Change (IPCC) — resolved to take more responsibility to be a public voice; not to lobby for a particular political response, but to explain and defend the science that is his life's work.
He wasn't alone. Increasingly, as the first decade of the century unfolded, Australia's most decorated scientists in climate fields were concerned that published evidence in their areas of expertise was being misused or ignored. Believing they faced a misinformation campaign driven by fossil-fuel interests and an intransigent political system, they formed Climate Scientists Australia as a means to improve the quality of public information and decision-making.
For some members, the challenge they faced was underscored in July when the Victorian Bushfires Royal Commission released its four-volume final report and made little reference to climate change.
It has been said so often that it should be well known by now: no extreme event can be definitively blamed on the surge in atmospheric greenhouse gases since industrialisation. But when events closely replicate what dozens of climate models have predicted will come, neither can they and climate change be divorced.
The 13 members of Climate Scientists Australia believe February 7, 2009, was such a case: 46.4 degrees in Melbourne — not just the city's hottest day on record, but more than 3 degrees warmer than February's previous maximum. Coinciding with turbulent winds and coming after a record 12 years of below-average rains, it added to an unprecedented score of 172 on the Forest Fire Danger Index, according to a report to the royal commission by Melbourne University fire ecologist Dr Kevin Tolhurst. Ash Wednesday in 1983 — the second-worst day for dangerous fire conditions — rated just 120, the devastating 1939 inferno 100.
In the October edition of the Bulletin of the Australian Meteorological & Oceanographic Society, Nicholls summarised: "A quantitative analysis leaves no doubt that the combination of weather conditions leading up to Black Saturday, and on the day, had not been observed previously in the 150 years of Melbourne instrumental weather data."
The commission, though, found neither the day nor the fires were unprecedented, accepting oral evidence from land and fuel management experts that the Black Saturday fires were not a shift from what had come before.
Nicholls, one of several scientists to lodge a submission with the commission linking the fires with human-induced climate change, was surprised. "I think a focus on the fact that we had not previously seen such extreme fire weather and climate conditions is important," he says.
"If we simply note that Black Saturday was just another instance of serious fires occurring in association with hot, dry, windy conditions, then we could lose sight of how extraordinary the weather conditions were, and we may not consider changes in strategy that could help us cope with even more extreme fires in the future."
The public debate over climate change has yielded its share of controversies, confected and otherwise, but in the eyes of leading scientists the royal commission's response is emblematic of the biggest of the past 10 years: the failure to convince policymakers and shapers to take the warnings of the world's most reputable scientific agencies seriously enough to respond effectively.
The global public's awareness of climate change grew significantly over the decade, but by this year, according to some polls, its acceptance of the science had diminished.
The decline was particularly marked in Britain and the US. Britain was home to the so-called "Climategate" affair, in which senior scientists were accused of manipulating data after ambiguous emails were leaked from the University of East Anglia. The scientists were exonerated of the most serious claims of dishonesty by a series of inquiries, but the damage was done — the findings clearing their names received only a fraction of the press coverage of the initial allegations. A separate investigation by the InterAcademy Council recommended changes to the IPCC, including greater care and transparency, but found its work synthesising published climate science was mostly successful.
In the US, there was a concerted attack from the resurgent Republican Party and influential parts of the media claiming climate science was a hoax and conspiracy. A University of Maryland study published this month found Fox News viewers were 30 percentage points more likely to incorrectly believe that most scientists do not agree that climate change is occurring, or that views are split.
The public mood was not helped by the debacle of the United Nations Framework Convention on Climate Change meeting in Copenhagen in December 2009, which left people with the not unreasonable perception that the world's leaders had no idea how to tackle the problem. The recent follow-up meeting in Cancun managed to glue the pieces of the broken talks back together, but left the most challenging issues in forging a new treaty to build on the Kyoto Protocol — which covers little more than a quarter of global emissions — to a later date.
Meanwhile, the claims made on climate change's behalf continued to mount. Delegates in Cancun were handed a report by aid agency Oxfam, quoting insurance agency Munich Re, which had linked 21,000 deaths in the first nine months of 2010 to climate change. It was twice the number of casualties caused by extreme weather in all of 2009. The mid-year floods that soaked a fifth of Pakistan alone killed about 2000 people and affected the lives of 20 million. The same weather system caused extraordinary summer heat in near-Arctic Russia that wiped out crops, caused rampant wildfires and doubled the usual summer death rate for Moscow. It rang alarm bells for those familiar with the IPCC's projection, based on more than 20 climate models that to date had proved remarkably accurate, that a significant temperature rise above pre-industrial levels would increase the likelihood of floods in southern Asia and the risk of heat waves and wildfires in Europe.
The New York Times — a journal of influence not known for running hard on the science of climate change — responded by running front-page pictures of the Pakistani and Russian disasters alongside a shot of storms pummelling Chicago under the headline "In weather chaos, a case for global warming".
"The climate is changing," the National Climatic Data Centre's Jay Lawrimore told the paper. "Extreme events are occurring with greater frequency, and in many cases with greater intensity."
Munich Re reported that its database of natural catastrophes showed the number of extreme weather events such as windstorms and floods had tripled since 1980 "and the trend is expected to persist".
Not everyone working in the area is comfortable with linking the current shift in extreme events with greenhouse gases. There is disagreement in the scientific literature over whether extreme weather disasters have started to worsen. According to one view, there is little to no change in the proportions of people affected once population growth is factored in.
What does not remain a contested area in the scientific literature is that the planet is getting hotter. Analysing the data from the world's three temperature datasets, the World Meteorological Organisation last month reported that the past decade was the warmest since instrumental measurement began in 1850, and 2010 was on track to be the hottest year, and certainly in the top three, regardless of the extraordinary snow dumps clogging European and US cities over Christmas. (There is significant evidence to suggest that global warming is responsible for the extreme northern winters of the past two years. An increase in air pressure in the Arctic atmosphere caused by heat coming off a relatively ice-free ocean is pushing cold air south.)
Eighteen countries broke their records for the hottest day ever this year. Only one year in the 20th century — 1998 — was warmer than any so far in the 21st.
The noughties was the decade of the killer heatwave. Western Europe was hit in August 2003, when extreme heat was estimated to have contributed to the deaths of 46,000. About a third of the deaths were in France. Usually home to mild summers, it was unprepared for the impact on the weak and elderly of a week's worth of days hotter than 40 degrees. There were widespread crop failures and forest fires, particularly in southern Europe. About a tenth of Portugal's forests burned.
In Australia, Victoria had never had three consecutive days above 42 degrees until January [2009], when there were three above 43 degrees. The horrendous bushfire death toll in early February was dwarfed by the "invisible disaster" of the January heatwave, which is estimated to have killed 500 people in Victoria, South Australia and Tasmania.
Perhaps the biggest step-change came in Russia this past northern summer, when at least five days in Moscow topped 100 degrees fahrenheit (37.78 degrees celsius) — a barrier that had never been crossed. An estimated 15,000 people died and the country's massive grain harvest was devastated by wildfire. According to Russian state weather service chief Alexander Frolov, it was the country's worst heatwave in a millennium. "Nothing like it can be seen in the archives," he said.
Nicholls says there are clear similarities between the three disasters, and others in Pakistan, Greece and California: "They have all been unprecedented, they all killed a lot of people and destroyed a lot of infrastructure."
Greenhouse gas emissions have continued to rise. Earlier this month the Mauna Loa Observatory in Hawaii showed that atmospheric carbon dioxide had reached 390 parts per million — a 40 per cent increase on pre-industrial levels.
All of this is in line with the IPCC's most recent assessment report, published in 2007, which found that there was at least 90 per cent certainty that most of the increase in the globe's temperature since mid-last century was due to the rise in industrial greenhouse gases. Even the world's most prominent climate sceptic, Lord Christopher Monckton, whose arguments have been shown by mechanical engineering professor John Abraham to repeatedly misrepresent the science he claims to be quoting, has acknowledged there is a greenhouse effect warming the planet, though he disputes its extent.
There is, of course, still significant uncertainty about the future impact of climate change. But the fundamentals predicted by climate models — marked declines in Arctic sea ice in summer, rising sea levels due to thermal expansion and glacier melt and increases in temperature — are being matched by observations.
That's the science. The response, the politics and economics, remain thornier still. The preferred model under the 1997 Kyoto Protocol is carbon trading, under which emissions are capped and pollution permits exchanged so that the cheapest way to meet the target can be found. This method has been adopted haphazardly across Europe, New Zealand and a band of US states, with more countries including Australia and China looking at signing up. There is near-universal agreement among economists that a carbon price is the most efficient way to reduce emissions, but carbon trading faces criticism that, while nice in theory, it is ineffective in the real world when it includes poorly policed offset schemes. For separate reasons, the US Congress has rejected a national trading scheme; Japan and South Korea have postponed a decision on theirs.
What are the hopes of a global solution to this diabolical problem? A recent prognosis by the Paris-based International Energy Agency found the national targets submitted under last year's loose Copenhagen Accord would put the world on a path of 3.5 degrees of warming by the end of the century. Even if you assume that countries introduce policies to back their international promises — Australia and the US, to name just two, currently have no way of meeting their targets — few scientists or policymakers expect the temperature rise to be kept within 2 degrees, the goal agreed under the UN process.
In Australia, next year will see a concerted effort from Labor, the Greens and significant parts of the business community to introduce a carbon price — most likely a tax that could evolve into carbon trading. If they succeed, attention is likely to turn to the challenge that has just begun to enter the public debate but will increasingly arise over the next decade: adapting to unavoidable change.
Adam Morton is environment reporter.