Some of the expected consequences of unchecked emissions-driven warming for doubling pre-industrial CO2 levels+* (via the IPCC AR4):
+ The resilience of many ecosystems is likely to be exceeded this century by an unprecedented combination of climate change, associated disturbances (e.g. flooding, drought, wildfire, insects, ocean acidification) and other global change drivers (e.g. land use change, pollution, fragmentation of natural systems, overexploitation of resources).
+ Over the course of this century, net carbon uptake by terrestrial ecosystems is likely to peak before mid-century and then weaken or even reverse, thus amplifying climate change.
+ Approximately 20 to 30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5 to 2.5°C.
+ For increases in global average temperature exceeding 1.5 to 2.5°C and in concomitant atmospheric CO2 concentrations, there are projected to be major changes in ecosystem structure and function, species’ ecological interactions and shifts in species’ geographical ranges, with predominantly negative consequences for biodiversity and ecosystem goods and services, e.g. water and food supply.
+ Crop productivity is projected to increase slightly at mid to high latitudes for local mean temperature increases of up to 1 to 3°C depending on the crop, and then decrease beyond that in some regions.
+ At lower latitudes, especially in seasonally dry and tropical regions, crop productivity is projected to decrease for even small local temperature increases (1 to 2°C), which would increase the risk of hunger.
+ Globally, the potential for food production is projected to increase with increases in local average temperature over a range of 1 to 3°C, but above this it is projected to decrease.
+ Coasts are projected to be exposed to increasing risks, including coastal erosion, due to climate change and sea level rise. The effect will be exacerbated by increasing human-induced pressures on coastal areas.
+ By the 2080s, many millions more people than today are projected to experience floods every year due to sea level rise. The numbers affected will be largest in the densely populated and low-lying megadeltas of Asia and Africa while small islands are especially vulnerable.
Industry, settlements and society
+ The most vulnerable industries, settlements and societies are generally those in coastal and river flood plains, those whose economies are closely linked with climate-sensitive resources and those in areas prone to extreme weather events, especially where rapid urbanization is occurring.
+ Poor communities can be especially vulnerable, in particular those concentrated in high-risk areas.
+ The health status of millions of people is projected to be affected through, for example, increases in malnutrition; increased deaths, diseases and injury due to extreme weather events; increased burden of diarrhoeal diseases; increased frequency of cardio-respiratory diseases due to higher concentrations of ground-level ozone in urban areas related to climate change; and the altered spatial distribution of some infectious diseases.
+ Climate change is projected to bring some benefits in temperate areas, such as fewer deaths from cold exposure, and some mixed effects such as changes in range and transmission potential of malaria in Africa. Overall it is expected that benefits will be outweighed by the negative health effects of rising temperatures, especially in developing countries.
+ Critically important will be factors that directly shape the health of populations such as education, health care, public health initiatives, and infrastructure and economic development.
+ Water impacts we’ll leave as a separate issue.
*We have the ability to mitigate emissions-driven change to the 2-3C level EDIT: but to date it looks unlikely that we will do so-that can of course change if the G8+5 set firm emissions targets. I want to emphasize that warming beyond 1.4-2ish C is not as of yet guaranteed. Additionally, most of the worrisome consequences lie beyond this range of warming.
Last edited by ghostface
on Sat Mar 29, 2008 8:37 pm, edited 2 times in total.
The tools of conquest do not necessarily come with bombs and explosions and fallout. There are weapons that are simply thoughts, attitudes, prejudices, to be found only in the minds of men. For the record, prejudices can kill and suspicion can destroy, and a thoughtless, frightened search for a scapegoat has a fallout all its own...