Globalwarming awareness2007

The likelihood that global temperatures will continue to significantly increase has led to proposals to mitigate global warming. Mitigation covers all actions aimed at reducing the negative effects or the likelihood of global warming.

There are five categories of actions that can be taken to mitigate global warming:

1. Reduction of energy use (conservation)
2. Shifting from carbon-based fossil fuels to alternative energy sources
3. Carbon capture and storage
4. Carbon sequestration
5. Planetary engineering to cool the earth, including screening out sunlight and increasing the reflectivity of the earth.

Strategies for mitigation of global warming include development of new technologies; carbon offsets; renewable energy such as biodiesel, wind power, and solar power; nuclear power; electric or hybrid automobiles; fuel cells; energy conservation; carbon taxes; enhancing natural carbon dioxide sinks; increased use of sulfate aerosols, which exhibit a cooling effect on the Earth; population control; and carbon capture and storage. Many environmental groups encourage individual action against global warming, often aimed at the consumer, and there has been business action on climate change.

The world’s primary international agreement on combating climate change is the Kyoto Protocol. The Kyoto Protocol is an amendment to the United Nations Framework Convention on Climate Change (UNFCCC). Countries that ratify this protocol commit to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in emissions trading if they maintain or increase emissions of these gases.

Although the governments of 163 countries ratified the Kyoto Protocol, (notably excluding the United States and Australia), there is a growing debate about how effective the Kyoto protocol has been. Some politicians, including President of the United States George W. Bush and Prime Minister of Australia John Howard have argued that the cost of mitigating global warming via the Kyoto protocol is too large to be practical. This view may be proving correct, as the signatories of the Kyoto protocol, including Europe and Japan, are currently struggling to meet their targets.[14] After only five years, Canada has given up entirely. Also, of the 163 countries that have signed and ratified Kyoto, only 31 are actually required to lower greenhouse emissions. Notable among those countries that have signed and ratified Kyoto but are not required to reduce greenhouse gas emissions are China and India with their huge populations and rapidly growing economies.

Some segments of the business community have accepted global warming and its attribution to anthropogenic causes as valid, as well as a need for actions such as carbon emissions trading and carbon taxes.

Adaptation strategies accept some warming as a foregone conclusion and focus on preventing or reducing undesirable consequences. Examples of such strategies include defense against rising sea levels or ensuring food security.

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Mitigation of global warming involves taking actions aimed at reducing the extent or likelihood of global warming. This is in contrast to Adaptation to global warming which involves taking action to take advantage of the positive effects of global warming while preventing or minimizing the negative effects.

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The predicted effects of global warming for the environment and for human life are numerous and varied. The main effect is an increasing global average temperature. From this flow a variety of resulting effects, namely, rising sea levels, altered patterns of agriculture, increased extreme weather events, and the expansion of the range of tropical diseases. 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 possible effects and our current understanding can be found in the report of the IPCC Working Group II; a discussion of projected climate changes is found in WG I.

Proposed responses to the effects of global warming fall into two categories: mitigation and adaptation.
Projected climate changes due to global warming have the potential to lead to future large-scale and possibly irreversible changes in our climate resulting in impacts at continental and global scales.

Examples of projected climate changes include:

• significant slowing of the ocean circulation that transports warm water to the North Atlantic,
• large reductions in the Greenland and West Antarctic Ice Sheets,
• accelerated global warming due to carbon cycle feedbacks in the terrestrial biosphere, and
• releases of terrestrial carbon from permafrost regions and methane from hydrates in coastal sediments.

The likelihood of many of these changes is uncertain. However, the probability of one or more of these changes occurring is likely to increase with the rate, magnitude, and duration of climate change.

Scientists are unable to accurately predict when various effects of global warming will occur or what the magnitude of the effect will be.

It is not possible to be certain whether there will be any positive benefits of Global Warming. What is known is that some significant negative impacts are projected and these drive most of the concern about global warming and motivates attempts to mitigate or adapt to the effects of global warming.

Most of the consequences of global warming would result from one of three physical changes: sea level rise, higher local temperatures, and changes in rainfall patterns (Figure 1). Sea level is generally expected to rise 50-200 cm in the next century (Dean et al. 1987); such a rise would inundate 7,000 square miles of dry land in the United States (an area the size of Massachusetts) and a similar amount of coastal wetlands; erode recreational beaches 100-200 meters, exacerbate coastal flooding; and increase the salinity of aquifers and estuaries (Titus 1989).

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