Two Degrees: China, South America, Europe...
More grim predictions from climate scientists, courtesy of Mark Lynas and his book

Droughts in Northern China. In a 1999 study, Chinese scientists showed that around 129 000 years ago, Northern China dried out and suffered continental-scale dust storms. China warmed by about 2 degrees during this period (the Eemian period) and the cold dry winter winds in the North responded much more quickly than the warm wet summer winds, causing massive dehydration. Lynas speculates that recent droughts in Northern China have the same root cause.

Chen, F. et al, 2003: "Stable East Asian monsoon climate during the Last Interglacial (Eemian) indicate by paleosol S1 in the Western part of the Chinese Loess plateau," Global and Planetary Change, 36, 171-9

Ocean acidification. Carbon dioxide dissolves in water to give carbonic acid. When there is enough CO2 in the atmosphere to raise temperatures by 2 degrees, there will also be enough to make large areas of the Southern Oceans and part of the Pacific effectively toxic to organisms with calcium carbonate shells. Affected organisms will include some varieties of plankton, the most important food source for ocean-dwellers. (Lynas likens this to spraying weedkiller over most of the world's land vegetation.)

Orr, J., et al, 2005: 'Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms,' Nature, 437, 681-6

The Royal Society, 2005: Ocean acidification due to increasing atmospheric carbon dioxide, Policy Document 12/05

Gazeau, F., et al, 2007: 'Impact of elevated CO2 on shellfish calcification,' Geophysical Research Letters, 34, L07603

Withering vegetation in Europe. The European heat-wave of 2003 caused -- among many other things -- a 30% drop in plant growth across Europe. Dying plants released an amount of carbon equivalent to one twelfth the annual carbon emissions from fossil fuels. Averaged across Europe, temperatures in Summer 2003 were 2.3 degrees above the norm.

Ciais, Ph., et al, 2005: 'Europe-wide reduction in primary productivity caused by the heat and drought of 2003,' Nature, 437, 529-33

Greenland melt. 115 000 years ago, melting ice meant that the sea level was 5-6 metres higher than today, yet average global temperatures were only 1-2 degrees warmer than today. Debate continues about how fast such melting can occur. But a 2007 study shows that sea levels are rising at 3.3mm a year, 50% faster than the 2007 IPCC report assumed.

Rohling, et. al., 2002: 'African monsoon variability during the previous interglacial maximum,' Earth and Planetary Science Letters, 202, 61-75

Tarasov, L., and Richard Peltier, W., 2003: 'Greenland glacial history, borehole constraints, and Eemian extent,' Journal of Geophysical Research, 108, B3, 2143

Rahmstorf, S., et al, 2007: 'Recent climate observations compared to projections,' Science, 316, 709

Drying India. A modelling study has concluded that a 2 degree increase in temperatures over India would decrease the agricultural yeild by 8%.

Kavi Kumar, K., and Parikh, J., 2001: 'Indian agriculture and climate sensitivity,' Global Environmental Change, 11, 147-54

South American water loss. In dry seasons the Rio Santa in Peru draws almost all of its flow from glacial melt. The melt from the glaciers is expected to drop by 40-60% by 2050. The Rio Santa powers hydroelectric turbines that are responsible for large-scale irrigation, 5% of Peru's electricity, and the drinking water for over a million people in the cities of Chimbote and Trujillo. (The 8 million people in Lima are also drawing for water on glaciers that are expected to dwindle in a 2-degree world, but no scientific studies have been conducted on Lima's glaciers.)

Kaser, G., et al, 2003: 'The impact of glaciers on the runoff and the reconstruction of mass balance history from hydrological data in the tropical Cordillera Blanca, Peru,' Journal of Hydrology, 282, 1, 130-44

Chevallier, P., et al., 2004: 'Climate change impact on the water resources from the mountains in Peru,' paper presented to the OECD Global Forum on Sustainable Development: Development and Climate Change, Paris, 11-12 November 2004

Juen, I., Kaser, G., and Georges, C., 2006: 'Modelling observed and future runoff from a glacierized tropical catchment (Cordillera Blanca, Peru),' Global and Planetary Change, 59, 1-4 37-48

California melting. California relies for its water on rivers stemming from the Sierra Nevada, Cascades and Rocky Mountains. During winter, more of this water is stored in "snowpack" in these mountains than in man-made reservoirs. A 2004 study predicted that this snowpack will decline by between a third and three-quarters in a 2 degree world. One study (Ruby Leung et al.) concludes: "Current demands on water resources in many parts of the West[ern US] will not be met under plausible future climate conditions, much less the demands of a larger population and larger economy."

Hayhoe, K., et al, 2004: 'Emissions pathways, climate change, and impacts on California,' Proceedings of the National Academy of Sciences, 101, 34, 12422-7

Ruby Leung, L., et al., 2004: 'Mid-century ensemble regional climate change scenarios for the western US,' Climatic Change, 68, 153-68

Crop failures. Crop failures are expected to be widespread in a hotter world, though failures in the tropics will be partially offset by successes at higher latitudes. In Mali, losses of maize crops are expected to leave up to three quarters of the population at risk of hunger, up from a third today. In Botswana, up to a third of the maize and sorghum crop could be wiped out due to a declining rainfall. A 2003 study predicts that North Sea cod population will disappear with around two degrees of warming.

Butt, T., et al., 2005: 'The economic and food security implications of climate change in Mali,' Climatic Change, 68, 355-78

Chipanshi, A., et al., 2003: 'Vulnerability assessment of the maize and sorghum crops to climate change in Botswana,' Climatic Change, 61, 339-60

Clark, R., et al, 2003: 'North Sea cod and climate change -- modelling the effects of temperature on population dynamics,' Global Change Biology, 9, 1669-80

Large-scale extinction. A study published in Nature in 2004 argued that over a third of all species on earth would be 'committed to extinction' if temperatures reach 2 degress in 2050. The lead author said in a Univeristy of Leeds press release that 'Well over a million species could be threatened with extinction as a result of climate change.' The study was based on models of expected movements of ecological niches due to changing climate.

Thomas, C., et al., 2004: 'Extinction risk from climate change,' Nature, 427, 145-8

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