Although climate scientists now prefer the term ‚climate change,‘ the phrase ‚global warming‘ has stuck in the minds of the public and media. We know that climate changes through time and that the earth has been both much warmer and cooler than it is today. So why are scientists concerned about this latest temperature rise and what makes it different? In 1988 the United Nations formed the Intergovernmental Panel on Climate Change (IPCC) to look at the evidence for climate change and provide summaries of the data to governments worldwide. The specific concern about current climate change was that human activity was a major factor in this global warming and that it has potentially disastrous consequences for mankind.
The science of global warming
The current thinking is that global warming is caused by a buildup of greenhouse gases in the atmosphere. These gases include water vapour, carbon dioxide (CO2), methane and ozone. As the sun’s rays strike the earth’s surface, they are reflected back into the atmosphere and are trapped by the greenhouse gases, causing the earth to stay warmer than it would otherwise be. This is vital for life on earth, but the theory is that a build up of anthropogenic (man-made) greenhouse gases is causing a rise in temperature which is not part of any natural earth cycle and is more rapid than previous temperature changes. The fear is that this could change weather patterns, cause sea levels to rise and seriously impact our lives.
How does man increase greenhouse gases?
Temperatures have risen about 0.8 of a degree since the 1800’s when accurate records first became available. This period coincides with the spread of the industrial revolution and the increased burning of fossil fuels. CO2 is a by-product of this activity. Deforestation, which reduces the planet’s ability to absorb CO2, and livestock producing methane are thought to be lesser factors. It should be pointed out that some scientists doubt that anthropogenic CO2 is the driving factor in global warming, but it is the current focus of the IPCC’s attempts to deal with the issue.
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