WEATHER forecasting is tough, but predicting climate changes is far more daunting. Even the most powerful supercomputers cannot truly mimic the complexities. Some problems:
Mapping changes in the weather is fraught with uncertainties.
WEATHER forecasting is tough, but predicting climate changes is far more daunting. Even the most powerful supercomputers cannot truly mimic the complexities. Some problems:
Conflicting Data: Climate data often gives ambiguous results. For example, while land and ocean surfaces show a warming pattern over the last 20 years, satellites and balloons that measure temperature in the lower air actually show a slight cooling trend. It is possible that traditional land-based measurements are being skewed by the "urban island" phenomenon, where city buildings and concrete absorb heat and make temperatures artificially high.
The Effect of Clouds: Global warming is expected to increase the buildup of clouds that, in turn, could serve as a sort of planetary thermostat to reduce surface temperatures. But since we still don’t understand exactly how clouds form, the actual effect is unclear. More over, sulphur dioxide and dust, collectively called aerosols, increase the whiteness of clouds, making them more reflective and less transparent to incoming sunlight. Scientists say aerosols may have offset as much as 20 per cent of the added greenhouse warming that would have already occurred.
"Missing Carbon"? Not all man-made carbon emissions can be easily accounted for. For the most part, natural uptake and release of carbon dioxide have been almost exactly balanced for thousands of years. But now, industry is adding to carbon levels at 7 to 8 billion tonnes a year. However, only about 3.5 billion additional tonnes are actually accumulating in the atmosphere each year. Scientists are clueless about the whereabouts of the rest . There’s more "mystery". Most man-made carbon dioxide comes from the northern hemisphere and, because of air-flow patterns, it is relatively difficult for the gas to cross the equator. But the difference in the levels of carbon dioxide between the northern and southern hemispheres is far smaller than computer models suggest.
The Inputs Problem: Finally, the lack of reliable and long-term climate data from different parts of the world has not helped matters. Little wonder then that different climate models come up with widely varying predictions.