THE YEAR IN CLIMATE SCIENCE

Roundup: Climate science in 2009; For climate science, the year 2009 brought significant discoveries and startling controversies
Kurt Kleiner, 29 December 2009 (UK Guardian)

[click through to source article for complete scientific journal references]

"…The year started out with some sobering, if not altogether surprising, news: overall, the Antarctic continent is warming…[The] studies provided the necessary evidence to show that human-induced warming is happening globally…[A]lthough temperatures rose overall during the twentieth century, distinct periods of warming and cooling of about 30 years each were superimposed on the warming trend…We might have entered such a phase in 2001–2002…[but] the Natural Environment Research Council and the Royal Society in the UK issued a statement that the previous ten years were the hottest on record.

"…In its 2007 report, the Intergovernmental Panel on Climate Change (IPCC) estimated a maximum sea level rise of 59 centimetres by 2100, but noted it was a low estimate…In March a Climate Change Congress in Copenhagen reported that sea levels could rise as much as one metre by 2100…In September…[researchers reported] that both ice sheets are melting much more rapidly than expected…[and] it's possible that sea levels could rise even higher than one metre by 2100…But the case on sea level rise isn't completely closed…"

There is no longer any doubt -- both poles are melting. (click to enlarge)

"Amidst continued discussions on…whether to stabilize atmospheric carbon dioxide concentrations at 450 or 350 parts per million, and whether peaking global emissions by 2015 or 2020 will be enough…a group of scientists suggested it would be easier to concentrate on…One trillion tonnes…the limit…on our cumulative carbon dioxide emissions if we are to have a reasonable chance of avoiding warming above 2 °C…[W]e've already released more than half a trillion tonnes since the year 1750…At current emissions rates, we'll reach that number in 40 years…[but] decision-makers [may use this as an excuse to]…put off action…

"With carbon emissions still rising, and political foot-dragging continuing, some scientists began to consider what the world will look like if we miss the target of limiting global temperature increase to 2 °C above pre-industrial levels…Even if emissions peak in 2015 and decrease by three per cent per year, there's an even chance we'll exceed 2 °C…As a precaution, we should begin planning now to adapt to 4 °C…[which could cause] the destruction of US$1 trillion worth of gross domestic product and displacement of 146 million people if sea levels rise a metre…"

The weight of climate change will soon come down on us. (click to enlarge)

"During 2009, geoengineering took a few steps away from science fiction and towards reality. The idea that we ought to consider actively taking control of the climate has previously seemed fanciful, if not downright dangerous. But as emissions have continued to rise, the idea has become less marginalized…In August the UK Royal Society released a report that said geoengineering might soon be our only hope…Man-made aerosols have been thought to counter global warming by reflecting solar radiation…[but research] concluded that they have different effects depending on the types of clouds and regions in which they form…The jury is still out on the overall influence…[A report said] glaciers in the Himalayas are not melting…[and another found] that glaciers are in fact rapidly dwindling…Changes in glaciers seem to vary depending on location and elevation, and there's not enough data to draw a general conclusion…

"…[T]housands of e-mails and documents were stolen from a server at the University of East Anglia Climatic Research Centre in the UK…'Climategate'…caused delight among climate change deniers and major embarrassment for some climate scientists…What the e-mails do not show, however, is a grand conspiracy to concoct global warming. Instead, they show sincere researchers struggling to do good work in a highly politicized environment — and sometimes losing their tempers…[but as NASA climatologist Gavin Schmidt said,] 'Science doesn't work because we're all nice...Newton may have been an ass, but the theory of gravity still works.'"