Attributed and Expected Effects of Global Warming

The predicted effects of global warming for the environment and for human life are numerous and varied. Some effects on both the natural environment and human life are already being attributed at least in part to global warming, such as glacier retreat, ice shelf disruption (e.g. Larsen Ice Shelf), rise in sea level, changes in rainfall patterns, increased intensity and frequency of hurricanes and extreme weather events. While changes are expected for overall patterns, intensity, and frequencies, it is difficult or impossible to attribute specific events (such as Hurricane Katrina) to global warming.

The main effect is - not surprisingly - an increasing global average temperature. From this may flow a variety of resulting effects as previously discussed, such as:

• rising sea levels
• altered patterns of agriculture
• increased extreme weather events
• reductions in the ozone layer
• increased intensity and frequency of hurricanes and extreme weather events
• spread of diseases such as malaria and dengue fever
• mass extinction events

In some cases, the effects may already be occurring, although it is generally difficult to attribute specific natural phenomena to long-term global warming. The extent and likelihood of these consequences is a matter of considerable political controversy; and in the details, a matter of some scientific uncertainty. A summary of probable effects and recent understanding can be found in the report of the IPCC Working Group II. It is not certain if there will actually be any positive benefits of Global Warming, though some northern climates have already been enjoying shorter and warmer winters than they are used to. Almost all scientists agree, however, that the long-term negative effects would out-weigh any short-term positive effects.

What is known is that some significant negative impacts are projected and these drive most of the concern about global warming. And the two main ways of addressing Global Warming issues to date have been Mitigation and Adaptation. Mitigation is basically concerned with reducing and even preventing the emissions of greenhouse gases responsible for climate change, so that less change occurs. Adaptation, on the other hand, attempts to deal with the actual consequences of warming and other aspects of climate change which are already happening and/or likely to occur in the future. Policymakers are now examining these two types of responses, including how much attention and what resources to devote to each one and how to find a balance between mitigation and adaptation.