Three Degrees: Botswana dunes, Indian monsoon...
More consequences of global warming, according to peer-reviewed science cited in Mark Lynas' book. (But why?)

Botswana sand dunes. Large parts of the Kalahari desert are covered in a layer of brush and scrub, and can be farmed. At least two studies, the latest in 2005, have suggested that by the time the globe hits 3 degrees the Kalahari hills will have "remobilized": a combination of high winds, high temperatures and low rainfall will strip them of their fertile cover, making then unsuitable for crops and animals.

Thomas, D., et al, 2005: 'Remobilization of the southern African desert dune systems by twenty-first century global warming,' Nature, 435, 1218-1221

Pliocene warming. 3m years ago the Arctic and Antarctic seas were clear of summer ice, shrubs grew in the Transantarctic mountains, 500km from the south pole, and were around 25m higher than today. Scientists think CO2 is mainly responsible for the temperature rise. The overall temperature at this time was around 3 degrees higher than today. CO2 concentrations were about the same as they are today. Thousands of years passed before this temperature and concentrations warmed the poles, but the similarity to today's figures is alarming.

Francis, J., and Hill, R., 1996: 'Fossil plants from the Pliocene Sirius Group, Transantarctic Mountains; evidence for climate from growth rings and fossil leaves,' PALAIOS, 11, 4, 389-396

Haywood, A., and Williams, M., 2005: 'The climate of the future: clues from three million years ago,' Geology Today, 21, 4, 138-143

Haywood, A., and Valdes, P., 2004: 'Modelling Pliocene warmth: contribution of atmosphere, oceans, and cryosphere,' Earth and Planetary Science Letters, 218, 363-77

Forest fires in Australia. The CSIRO Atmospheric Research has predicted that 35 degrees days in Queensland could occur 2 to 7 times more often than they do today. Higher winds, and up to 25% less rainfall, would also add to the fire risk in the state. This would lead to more events like the 2003 conflagaration outside Canberra, which killed 4 people, destroyed 500 buildings, and in ten minutes released more energy than the Hiroshima atomic bomb.

Hennesseym K., et al., 2004: 'Climate Change in New South Wales: Part 2 -- Projected changes in climate extremes,' CSIRO, November 2004, 7pp

Fromm, M., et al., 2006: 'Violent pyro-convective storm devastates Australia's capital and pollutes the stratosphere,' Geophysical Research Letters, 33, L05815

The Arctic again. A 2000 study predicted that around 80% of Arctic sea ice would disappear once the mercury hit 3 degrees. A more recent study (in 2007) concluded that Arctic melting was running 30 years ahead of its forecast rate.

Johannessen, O., et al., 2004: 'Arctic climate change: observed and modelled temperature and sea ice variability,' Tellus, 26A, 328-41

Stroeve, J., et al, 2007: 'Arctic sea ice decline: Faster than forecast,' Geophysical Research Letters, 34, L09501

Central America. Drought is forecast for Central America, with the Hadley Centre predicting a rainfall decline of 1-2mm per day in this region. This would leave the area vulnerable to calamities like the drought in 2001, which led to food shortages among around 1.5 million people. Severe warming could lead to droughts on the scale of those that laid waste to the illustrious Mayan civilisation in the early Medieval period.

Johns, T., et al., 2003: 'Anthropogenic climate change for 1860-21-- simulated with the HadCM3 model under updated emission scenarios,' Climate Dynamics, 20, 583-612'

Indian Monsoon. The monsoon over the subcontinent is expected to become heavier but less regular, leading to more extreme flooding in India and Bangladesh and a greater likelihood of dry periods in the region. Given the vast populations in the area, and their reliance on agriculture, "The reliability of the Monsoon is...a matter of life and death for millions of people" (Lynas' words).

May, W., 2004: 'Simulation of the variability and extremes of aily rainfall during the Indian summer monsoon for present and future times in a global time-slice experiment,' Climate Dynamics, 22, 183-204

Ueda, H., et al., 2006: 'Impact of anthropogenic forcing on the Asian summer monsoon as simulated by 8 GCMs,' Geophysical Research Letters, 33, L06703

Dairaky, K., and Emori, S., 2006: 'Dynamic and thermodynamic influences on intensified daily rainfall during the Asian summer monsoon under doubled atmospheric CO2 conditions,' Geophysical Research Letters, 33, L01704

Drying of the Indus river. The Indus river runs from the Karakoram range that straddles Pakistan and south-west China. Karakoram is the largest glaciated area outside the poles. According to a 2005 WWF study, all of the major ice-capped areas in the Karakoram and Himalayan region are melting at an accelerated rate. A study commissioned by DFID concluded that after a period of high flows due to meltwater, the Indus will contain 20 to 40 percent less water by 2080. With few other sources of water available to it, either inside or outside the coutry, Pakistan could plunge into a food and water crisis.

WWF Nepal Program, 2005: An Overview of Glaciers, Glacial Retreat, and Subsequent Impacts in Nepal, India, and China, WWF, March 2005, 70pp

Rees, G., and Collins, D., 2004: An Assessment of the Potential Impacts of Deglaciation on the Water Resources of the Himalaya, DFID KAR Project No. R7980, 54pp and Annexes

New York floods. The New York metropolitan area has 20 million people, 2,400km of coastline, and a network of rail, tunnel and airport facilities whose entrances lie 3m or less above sea level. In a 3 degree world the sea level is expected to rise between 25cm and 1m, so that today's one-in-100-year flood could be a one-in-4-year event by 2080. Floods in 1992 and 1999 crippled the NYC transport system and left areas of Lower Manhatten under 1m of water.

Gornitz, V., et al., 2002: 'Impacts of sea level rise in the New York City metropolitan area,' Global and Planetary Change, 32, 61-88

North Sea storms. A 2001 study based on Hadley Centre models mirrors the predictions for New York weather: "In the southern North Sea," one of the authors wrote, "by the 2080s, a typical return period for what is now a 150-year event will be seven or eight years." The 1953 flood that caused 300 deaths in the UK and 1,800 in the Netherlands, and has been called UK's worst-ever natural disaster, was described at the time as a one-in-150-year event.

Lowe, J., et al., 2001: 'Changes in occurrence of storm surges around the United Kingdom under a future climate scenario using a dynamic storm surge model driven by the Hadley Centre models,' Climate Dynamics, 18, 179-188

The "sixth mass extinction of life." "Living dead" is the name ecologists give to populations whose numbers are so low they are doomed to extinction. A paper published in Nature in 2004 concluded that between a half and a third of species alive today will join the "living dead" by 2050 if the planet warms by over 2 degrees by that date.

Thomas, C., et al, 2004: 'Extinction risk from climate change,' Nature, 427, 145-148

Deserts in the Amazon. A 2000 paper from the UK's Hadley Centre (a world leader in climate modeling) predicted that a 3 degree temperature rise would commit the globe to another 1.5 degree increase by 2100 -- even if human carbon emissions stabilised once we hit 3 degrees. According to the Centre's models, 3 degrees of warming would "put the carbon cycle into reverse," as Lynas puts it: trees and plants would stop absorbing CO2 and start releasing it as they withered and died. The Amazon, 7 million km2 of lush vegetation, would be particularly vulnerable to this feedback effect: the Hadley models predict that by 2100 rainfall will drop to almost zero in some areas of the jungle, with temperatures soaring to 38 degrees on average.

[It must be said -- and Lynas says it -- that there is no consensus on the question of whether Amazon rainfall will drop low enough to trigger the feedback effect. A 2007 survey concluded that nearly half of the studies on the topic predicted an increase of rainfall for the Amazon. I include this topic because Amazon collapse is often cited as a key tipping point, and because if it did happen the consequences would be enormous.]

Cox, P., et al, 2000: 'Acceleration of global warming due to carbon cycle feedbacks in a coupled climate model,' Nature, 40, 184-7

Li, W., et al, 2007: 'Future precipitation changes and their implications for tropical peatlands,' Geophysical Research Letters, 34, L01403

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