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The rapid increase in carbon dioxide emissions observed during the last 250 years is expected to continue for several decades to come. Various scenarios have been examined, depending on factors like fuel use and efficiency. Even the best case scenario predicts further increases in carbon dioxide emissions until about 2040.

Many of the scenarios indicate that by the middle of the 21st century emissions of carbon dioxide should ate least start to level off, though some predict increase in emissions throughout this century.


Though the different scenarios predict a wide range of trends in carbon dioxide emissions, the predicted net effect on atmospheric carbon dioxide concentrations in the future is fairly consistent.

All predict further increase in carbon dioxide concentrations by the end of the is century, with some of the scenarios predicting a doubling or even trebling of today's levels of carbon dioxide.

If the predicted increases in greenhouse gas concentrations are then translated into temperature changes, a global temperature increase of between 1 and 5.5 degrees centigrade is predicted for 2100..

The average predicted temperature increase over the next 100 years is around 3 degrees centigrade. This compares to an increase of about 1 degree centigrade due to previous man-made greenhouse gas emissions.

The large amount of variation between predictions of the different scenarios underlines the complexity involved in making such predictions and the large amount of uncertainty inherent in climate change models.

A common feature of global warming stories in the media is sea level rise. Sea level rise, through the thermal expansion of water and icemelt around the world, poses a potentially very serious threat to millions of people.

Like temperature change, predictions vary widely, from a low of 20 cm to a high of around 60cm.



The impact of such sea level rise is likely to be greatest in those low lying countries, like Bangladesh, least able to adapt to the sea level rise by building expensive sea defences.

Figures reproduced with the kind permission of the Intergovernmental Panel on Climate Change (IPCC).

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