More than 4 trillion tons of ice fromGreenland and Antarctica has melted inthe past 20 years and flowed into theoceans, pushing up sea levels 11 mm.Shepherd et al. (Dec 2012). AReconciled Estimate of Ice-Sheet MassBalance. Science.
The U.S. is about to register the warmest year on record in the lower 48 states, and the world its ninth-hottest, a United Nations agency said in a report, adding new urgency to the quest to control global warming.Two-thirds of the U.S. states suffered drought this year, while heat waves hit across Europe and in Morocco, Jordan, China and Russia, the World Meteorological Organization said in a report released in Doha, where UN climate talks began this week. It noted Arctic sea ice shrank to its smallest on record.“The alarming rate of its melt this year highlighted the far reaching changes taking place on Earth’s oceans and biosphere,” WMO Secretary-General Michel Jarraud said in a statement. “Climate change is taking place before our eyes and will continue to do so as a result of the concentrations of greenhouse gases in the atmosphere, which have risen constantly and again reached new records.”Guardian Environmental News Online
Climate change is one factor that appears to bedriving at least some of the current bark beetleoutbreaks. Temperature influences everything in abark beetle’s life, from the number of eggs laid by asingle female beetle, to the beetles’ ability todisperse to new host trees, to individuals’ over-winter survival and developmental timing. Elevatedtemperatures associated with climatechange, particularly when there are consecutivewarm years, can speed up reproductive cycles andreduce cold-induced mortality. Shifts in precipitationpatterns and associated drought can also influencebark beetle outbreak dynamics by weakening treesand making them more susceptible to bark beetleattacks.U.S. Forest Servicehttp://www.fs.fed.us/ccrc/topics/bark-beetles.shtml
This figure shows the estimated reduction in the U.S. GDP over the period 2010 to 2050from changes in precipitation, an economically important climatic feature. The values onthe solid red line represent the total cost over the 40-year period – placing a 50%probability on the loss of $1.1 trillion – the equivalent of ~7 million jobs. Note how fastthe losses accelerate at the lower probabilities. The dashed lines represent theuncertainty of the best-estimate exceedance-probability values. For any given point onthe best-estimate line, it is highly likely (.95 statistical probability) that the impact will liesomewhere between the corresponding values on the enveloping dashed lines based onprojections with available data.
Antonio Guterres, the UN high commissioner for refugees, told the Guardian:"Climate change is today one of the main drivers of forced displacement, both directlythrough impact on environment - not allowing people to live any more in the areaswhere they were traditionally living - and as a trigger of extreme poverty and conflict."
“Climate change is likely to lead to someirreversible impacts on biodiversity. There ismedium confidence that approximately 20%–30% of species assessed so far are likely to beat increased risk of extinction if increases inglobal average warming exceed 1.5–2.5ºC, relative to 1980–99.”Nobel Lecture by R. K. Pachauri, Chairman ofthe Intergovernmental Panel on ClimateChange (IPCC), Oslo, 10 December 2007.
“As global average temperature exceedsabout 3.5 ºC, model projections suggestsignificant extinctions (40%–70% ofspecies assessed) around the globe. Thesechanges, if they were to occur would haveserious effects on the sustainability ofseveral ecosystems and the services theyprovide to human society.”Nobel Lecture by R. K. Pachauri, Chairmanof the Intergovernmental Panel on ClimateChange (IPCC), Oslo, 10 December 2007.“Localized ecological systems are known toshift abruptly and irreversibly from one state toanother when they are forced across criticalthresholds. Here we review evidence that theglobal ecosystem as a whole can react in thesame way and is approaching a planetary-scalecritical transition as a result of humaninfluence.”Barnosky, A. et al. Approaching a state shift inEarth’s biosphere.Nature 486, 52–58 (07 June 2012)