Global Warming is defined as the increase of the average temperature on Earth. According to the Fourth Assessment Report 2005 of the United Nations Intergovernmental Panel on Climate Change (IPCC), the average global air temperature near the Earth’s surface increased a little less than 1° Celsius (0. 74 ± 0. 18°C, or 1. 3 ± 0. 32° Fahrenheit) during the last hundred years. Their data showed that an increase of one degree Celsius makes the Earth warmer now than it has been for at least a thousand years.
Out of the 20 warmest years on record, 19 have occurred since 1980. Furthermore, they concluded that “most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations” via the greenhouse effect. Over 25 scientific societies, including the national academies of science of G8 nations endorsed the findings.
Indeed, warming of the climate system is unequivocal and is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level. In fact, in 2005, the Zurich – based World Glacier Monitoring Service stated that European glaciers had lost half their volume since 1850. And in October this year, British researchers showed that warmer temperatures were responsible for a 2. 2 percent increase in the Earth’s humidity over the last 30 years.
Global warming causes widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones (typhoons and hurricanes). Other indirect effects include changes in agricultural yields, trade routes, glacier retreat, species extinctions and increases in the ranges of disease vectors. Though natural cycles of climate change have existed in the past, scientists have shown that the latest warming trend is largely the result of the burning of fossil fuel.
There is no doubt that human activity since the industrial revolution has increased the concentration of various greenhouse gases leading to increased carbon dioxide (CO2), methane, chlorofluorocarbons (CFCs) and nitrous oxide (NO). Burning fossil fuels, trees and agricultural wastes dramatically increased levels of atmospheric greenhouse gases particularly CO2 as do landfills, oil refineries and coalmines. While these gases help us from freezing to death, researchers worry that we produce them at concentrations that are far too high.
“CO2 has increased 35 percent since the beginning of the industrial era,” says Gavin Schmidt a climatologist with NASA’s Goddard Institute for Space Studies in New York. “Methane has more than doubled while nitrous oxide has gone up to 17%”. While we have stabilized our CFS’s and methane emissions, we have not done the same with CO2 so far. The carbon dioxide in the atmosphere continues to rise by about 0. 4% per year because fossil fuels that produce it fill 85 percent of our energy requirements.
Continued greenhouse gas emissions at or above current rates would cause further warming and induce many changes in the global climate system during the 21st century that would very likely be greater and more devastating than those observed during the 20th century. There is convincing evidence of global warming and we are experiencing its effects. We need to act now before the situation becomes worse and solutions become out of hand. Individuals, corporations, states and nations must exert a collective effort to find ways and implement actions that would curtail global warming. The sooner we act, the easier our task will be.