الموارد

The Intergovernmental Panel on Climate Change (IPCC), in its 2007 report, stated unequivocally that humans are contributing to climate change. People’s actions are intensifying the climate’s natural variability, and the Earth’s temperature is rising. Scientists make a distinction between climate variability (where climatic variations are attributable to natural causes) and climate change (where human activities are altering the atmospheric composition). Human induced (or anthropogenic) climate change is caused by increased production of greenhouse gases, including carbon dioxide (CO2), methane and nitrous oxide. Carbon dioxide, the main contributor, is produced primarily by the burning of fossil fuels — oil, gas and coal. Although methane occurs in smaller quantities than CO2, it has higher warming effects. Increased methane production is linked to increased levels of livestock farming for meat production. Warming of permafrost areas in Siberia and Canada may also contribute significantly to an increase of methane emissions, since permafrost lakes store methane gases. Increases in greenhouse gas production are directly linked to the post-1750 period of industrialisation in Western countries. These gases now far exceed the natural rate of greenhouse gas production as measured in pre-industrial era ice cores spanning many thousands of years. The IPCC projects that global average temperatures are likely to rise by 1.8 - 4 degrees Celsius by 2100. This might sound small, but the difference between today’s temperatures and the last Ice Age is around 4-5%. A small temperature rise is likely to have a substantial impact. It may also take many years for the real impact of current rises in temperature to show. Even if people substantially reduced CO2 emissions tomorrow, the atmosphere would go on warming for a long time to come. Changes in temperature will impact on the whole of the Earth’s system, and on human activities everywhere. Projected impacts include warming of the oceans, melting of the icecaps, sea level rise, unpredictable weather patterns, increased flooding and droughts, loss of biodiversity, changes in agricultural productivity, increased health risks, massive human migration and economic decline. Scientists are worried that change will be faster than expected due to ‘positive feedback’, which is a process where the warming fuels itself, causing accelerated temperature increase. The acceleration of climate change needs to be reduced urgently, and everyone everywhere needs to be involved.