Challenge North Leigh

“Six Degrees: Our Life on a Hotter Planet” by Mark Lynas

A Three Degree Rise – and beyond? A Summary of Conclusions.

In the “three degree” scenario, Africa will be split between the north, which will see a recovery of rainfall, and the south, which becomes drier and beyond human adaptation. Wind speeds will double leading to serious erosion of the Kalahari desert.

The last time the world experienced a three degree temperature rise was during the geological Pliocene Age (3 million years ago). The historical period of the earth’s history was undoubtedly due to high CO2 levels (about 360 – 440ppm – almost exactly current levels)

Likely to see major increase in activity of the so-called “el nino” effect. In such a scenario, the following are likely:-

• UK can expect drier winters

• Indian monsoon rains will fail. Monsoons are essential to 60% of the world’s population. In a 3° world monsoons will become more variable either failing entirely or causing devastating flooding.

• The Himalayan glaciers provide the waters of the Indus, Ganges and Brahmaputra, the Mekong, Yangtze and Yellow rivers. In the early stages of global warming these glaciers will release more water but eventually decreasing by up to 90%. Pakistan will suffer most, as will China’s hydro-electric industry.

• Amazonian rain forest basin will dry our completely with consequent bio-diversity disasters

• In Brazil, Venezuela, Columbia, East Peru and Bolivia life will become increasingly difficult due to wild fires which will cause intense air pollution and searing heat. The smoke will blot out the sun.

• Drought will be permanent in the sub-tropics and Central America

• Australia will become the world’s driest nation. Days when the temperatures exceed 40° will increase sixfold, the drought frequency will triple and rainfall plummet by 25% with extreme winds. Australia’s main rivers for water supply will lose between 25% and 50% of their flow. Perth particularly vulnerable.

• The western seaboard of the US will be especially vulnerable to drought. Snowmelt will reduce dramatically. Snowless Springs, hotter summers, harsher droughts and wild fires without water to fight them will become common-place.

• By contrast, New York will have too much water! It will be subject to storm surges. Sea levels are already 25cms higher. At 3° sea levels will rise to up to 1 metre above present levels. A 1 in a 100 year storm will happen every 20 years by 2050 and every forth year by 2080.

• In London, too, although the Thames Barrier will continue to give some protection, a 1 in 150 year storm will occur every 7 or 8 years by 2080.

• In the US Gulf of Mexico high sea temperatures will drive 180+ mph winds. Houston will be vulnerable to flooding by 2045. Galveston will be inundated.

• Hurricanes will devastate places as far removed as Texas, the Caribbean and Shanghai.

• A 3° rise will see more extreme cyclones tracking across the Atlantic and striking the UK, Spain, France and Germany. Holland will become very vulnerable. By 2070 northern Europe will have 20% more rainfall and at the same time the Mediterranean will be slowly turning to a desert.

• East Africa will become more humid encouraging a greater incidence of malaria and dengue fever.

• In the Arctic 80% of sea ice will have melted.

• Some northern regions will benefit from longer growing seasons (Norway, Finland) but will not compensate for loss of production elsewhere.

• Many plant species will become extinct as they will be unable to adapt to such a sudden change in climate. More than half Europe’s plant species will be on the “red list”.

The International Panel on Climate Change in its 2007 report concluded that all major planetary granaries will require adaptive measures at 2.5° temperature rise regardless of precipitation rates. US southern states worst affected, Canada may benefit. The IPCC reckons that a 2.5° temperature rise will see food prices soar. Population transfers will be bigger than anything ever seen in the history of mankind. This will inevitably lead to conflict and international wars.

Worse still, a “vicious circle” will develop under the three degree scenario:-

• Amazon rain forests dry out

• Wild fires develop

  • Fires release more CO2. In the Indonesian peat fires of ‘97/’98 2 billion EXTRA tonnes of CO2 were released

• Global warming intensifies as a result

• Vegetation and soil begins to release CO2 rather than to absorb it.

• Could push the 3° scenario to a 4° to 5.5° situation. (International Panel on Climate Change worst case scenario).

Many thanks to Colin Carritt for producing this sobering summary.

Geoff Feasey

5^th October 2009

This entry was posted on Monday, October 19th, 2009 at 8:06 pm and is filed under advice. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.