Future Climate Change
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Greenhouse gas concentrations in the atmosphere will increase during the next century unless greenhouse gas emissions decrease substantially from present levels. Increased greenhouse gas concentrations are very likely to raise the Earth's average temperature, influence precipitation and some storm patterns as well as raise sea levels (IPCC, 2007). The magnitude of these changes, however, is uncertain.
The amount and speed of future climate change will ultimately depend on:
- Whether greenhouse gases and aerosol concentrations increase, stay the same or decrease.
- How strongly features of the climate (e.g. temperature, precipitation and sea level) respond to changes in greenhouse gas and aerosol concentrations.
- How much the climate varies as a result of natural influences (e.g. from volcanic activity and changes in the sun ’s intensity) and its internal variability (referring to random changes in the circulation of the atmosphere and oceans).
Climate Models Virtually all published estimates of how the climate could change in the future are produced by computer models of the Earth’s climate system. These models are known as general circulation models (GCMs). According to the IPCC (2007):
It is important to recognize that projections of climate change in specific areas are not forecasts comparable to tomorrow’s weather forecast. Rather, they are hypothetical examples of how the climate might change and usually contain a range of possibilities as opposed to one specific high likelihood outcome. |
The following pages provide a summary of the projected changes in the atmosphere and climate over the next century based on the current state of knowledge:
- Future Atmosphere Changes in Greenhouse Gas and Aerosol Concentrations
- Future Temperature Changes
- Future Precipitation and Storm Changes
- Future Sea Level Changes
References
- IPCC, 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning (eds.)].