Background: Climate & Evolution
From Denial to Collapse
Colorado River reservoir levels reflecting a decade of drought
Ancient Kyoto, with its classic Buddhist temples and gardens was an auspicious location to negotiate a treaty to ‘prevent dangerous anthropogenic interference with the climate system’ (1997). The well-intentioned Kyoto Protocol was however fundamentally flawed. It failed to address destructive burning of tropical rainforests, which contributes 25% of GHG emissions. It exempted China and India from mandatory reductions, and they developed into major GHG polluters. China has since far surpassed the U.S. as the world's biggest carbon polluter.
Kyoto was rejected by the U.S., the source of a quarter of world GHG emissions. This reflected the overweening influence of its fossil fuels industry. In 2005, an extreme weather event, Hurricane Katrina, flooded New Orleans. In 2007, the director of the U.S. Hurricane Centre retiring after 38 years of government service, warned that greater disasters were inevitable. Also in that year, 90% of 6 southern states (California, Arizona, Nevada, Georgia, Alabama, Tennessee) were suffering the worst drought since the Great Depression, with major negative impacts on U.S. agriculture. The climate warming-wildfire link is now a special American concern. Wildfires have burned an area larger than the state of Idaho since 2000. Yet to date, the U.S. remains the principal obstacle to an effective global climate protection treaty.
Australia is the world’s greatest exporter of coal and generates its highest per capita carbon emissions. Its government refused to ratify the Kyoto treaty. Australia has been experiencing its worst drought for hundreds of years. Over an area the size of France & Germany combined, rivers and reservoirs have run dry. Farmers raise emaciated livestock. Cotton, wine grape and rice crops have collapsed. The authorities ended further agricultural irrigation to preserve the remaining drinking water. In the 2007 election, Australians decisively rejected an administration that had presided over this ecological disaster while refusing to ratify Kyoto. Australia well exemplifies the choice the world will have to make between agriculture and a fossil fuel economy. We must choose the survival option swiftly, or choice itself will be denied to us.
Arctic summer, 2007 : one million more square miles of open water
has appeared since satellite measurements began 30 years ago
Plants require narrow, specific ranges of temperature and soil moisture. A general rule of thumb among crop ecologists is that for every rise of 1C above the norm, wheat, rice and corn yields fall by 10%. Since we face warming of 4-5C or more this century on the business-as-usual emissions path, this path risks the destruction of much of the world's food supply.
IPCC  predictions indicate that rain-dependent agriculture in certain African countries could suffer a 50% yield reduction by 2020 on current global warming trends. The implications of climate warming for world cereal production and food supply are already becoming apparent in the form of substantial crop yield reductions in Australia, Africa, China and India. Taken as a whole, these dangers completely outweigh the so-called difficulty of switching systematically to renewable energy, smart energy use and of protecting the Earth’s remaining rainforests.
Leading climatologist, Dr James Hansen of NASA  believes that genuine progress must occur by 2015 to reverse the flow of carbon gas into Earth’s atmosphere. If we fail this challenge, we will trigger ecological tipping points such as a die-off of the Amazon Rainforest, or general melting of Siberian, Canadian and Tibetan permafrost. Either of these outcomes would release vast, critical levels of greenhouse gas into the atmosphere.
The extent of melting of Arctic sea ice (summer 2007 is pictured above) exemplifies the first stage of a positive feedback loop. It increases the possibility of an ‘albedo flip’ for the terrestrial Greenland ice sheet. The latter would be a nonlinear event  of the kind that whipsawed the early Earth between climatic extremes. Such effects, irreversible and beyond human modification, are to be avoided at all costs. At the juncture of the Paleocene and Eocene eras, 55 million years ago, there was a runaway global warming event involving release of methane from frozen stores in the deep oceans. This caused a great extinction of species. This is why the celebrated Bulletin of the Atomic Scientists now ranks the threat of global warming to civilization as equivalent to that of nuclear war:
Both the nuclear menace and a runaway greenhouse effect are the result of technology whose control has slipped from humans' grasp. But it is also within our power to pull them back under control… While the harm done to the planet by carbon-emitting technologies is more gradual than nuclear war, it could be equally catastrophic to life as we know it, and irremediable .
1. 4th Assessment Report of the IPCC 
2. J.Hansen  Keynote presentation to U.S. National Academy of Sciences
3. Bulletin of the Atomic Scientists .