Global Warming is a gradual increase in temperatures across the whole of planet earth. Both natural events and human activities on the earth are contributing to this change. This fact is now very well documented and accepted by scientists as true: the earth is the currently the hottest is has been for over 400 years- and it may be that it hasn’t been so hot in the last 2000 years or so. Measurements indicate that the average global surface temperature has increased by around 0.3-0.6 degrees centigrade over the last hundred years, the largest increase in surface temperature over the last 1,000 years and scientists are predicting that this increase will speed up over the next hundred years. The global warming is ascribed to the increase of greenhouse gases (mainly carbon dioxide and methane) in the earth’s upper atmosphere. This buildup of gases is chiefly caused by humans burning fossil fuels, by industry, farming and deforestation. Average global temperature may increase by around 1.4 to 5.8 degrees centigrade by the end of the 21st century, and though these number sound small they are actually smaller than the temperature differences between an ice age and ice-free age. The rise in temperatures will initiate significant changes in climate-not only more hot days but changes in rainfall patterns and weather systems. Climate change is probably already having an impact on the earth’s systems. In the future the problems that will be the effect of rising sea level and increasing spread of deserts and droughts are also likely to affect the developing countries more than rich countries.
Global warming and the food supply
With the increase of temperatures known now as Global Warming agriculture will become more and more difficult.
Food crops will suffer increasingly from diseases and fungal infections which will impact on quality and overall size of the harvest. Without the normal seasons and cold/frost cycles which reduce the numbers of pests and disease spores invasive species will increase.
As natural disasters increase more food crops will be destroyed by floods, hailstones, storms and freak weather conditions at the wrong time of year.
Food crops that had been plenteous may become scarce and thus more expensive. As natural disasters increase – plus a continuing rise in the world population-the demand for staple food crops will increase leading to prices rises and shortages.
The pressure of increased population on the land together with global warming is also leading to desertification. This is when more and more land is becoming desert. Global warming is leading to higher temperatures and reduced rainfall in some areas leading to prolonged drought There are, however, other factors contributing to and exacerbating this. Firstly when trees are cut down to clear the land-the process of deforestation- leads directly to lower rainfall and higher temperatures. Contributing to erosion are overcultivation, the process of trying to grow too many crops year by year on the same land, and overgrazing where animals remove the vegetation and expose the soil.
Many people now recognize the problems and argue for sustainable development so that some of these processes can be, if not reversed, at least slowed down to enable the earth to recover.