New scientific report on the consequences of the gobal warming

Le Monde, édition du 20.03.2007

Shortages of water, floods, lower agricultural outputs, multiplication of fires, decline of the biodiversity… The scientists of the Intergovernmental Group of Experts on the Evolution of Climate (GIEC) are publishing new evaluations of the consequences of the global warming and the confirmation of the bond between this phenomenon and the multiple disturbances already noted on the planet.
These data will be debated between several hundreds of scientists and representatives of 190 countries, from April the 2nd to April the 5th in Brussels.
After the approval of the first part of the evaluation report of the GIEC in Paris, on February the 2nd (which had ratified the responsibility of human activities in the global warming), the second chapter will deal with its consequences.


The direct consequences of the global warming:
- instability of the grounds in mountains,
- melting of the permafrost,
- modifications of the flora and the fauna in the polar areas,
- increase of temperatures of lakes and rivers,
- precocity of the budding of vegetation and migrations of birds,
- modifications of the distribution of algae, fishes, plankton, etc.

To underlie the fact that the rhythm of increase in the average temperature will depend on the actions taken to reduce the gas emissions for purpose of greenhouse, the evaluations of the future impacts are made by taking in reference rises of temperatures, without mention of dates.

If we count a rise of temperature between 2°C and 4,5°C above the values of 1990, scientists evaluate:
- between 1 and 3,2 billion the number of people touched by water shortages
- hundreds of million the number of people threatened by the rise of the level of oceans. Indeed, if the reheating reaches 4°C, a fifth of the world population would be confronted with floods
- agricultural outputs would decline everywhere if the reheating reaches 3°C
- in the South of the planet, capacities of adaptation of many species would be exceeded. Up to 120 million additional people would then be exposed to famine. Scientists envisage an increase in the number of deaths due to heat, dryness, floods, diseases related to water, as well as massive extinction of species, and major upheavals in ecosystems.

Several areas of the world are regarded particularly threatened, as small islands, or Arctic, and:
- Africa, with water shortages and loss of arable grounds, is also considered to be very vulnerable, because of the weakness of its capacities of adaptation.
- The estuaries of Asian rivers, very populated, also form part of the most exposed zones. If the global warming is not braked, in Asia, the melting of the glaciers of the Himalayas will involve floods, crumbling, disturbances in the water supply.
- In the South of Europe, the water availability will decrease in 5% to 35%, with consequences on the agricultural and hydroelectric production, and the frequency of fires. On the other hand, it will increase by 10% to 20% in the North of the continent, involving floods.
- In South America, the vegetation could suffer important disturbances (replacement of the tropical forest by savanna). In dry areas, agricultural lands would become unsuitable with the cultures.
- North America will have to face a strong competition for the use of water, waves of heat, and the increase of fires.

Scientists underlie that the actions of adaptation (modification of the use of grounds, of infrastructures, and increased protection of the ecosystems) to climatic changes are not very developed.

However, even if the gas emissions for purpose of greenhouse would decrease quickly, benefit of that would be felt only several decades after. Such measurings are thus essential, according to experts' of the GIEC.