Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface;
In turn, the earth radiates energy back into space;
Some atmospheric gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse;
These gases are therefore known as greenhouse gases;
The greenhouse effect is the rise in temperature on Earth as certain gases in the atmosphere trap energy.NASA’s Goddard Institute of Space Studies (GISS) tracks atmospheric global temperature climate trends. As environmental engineer, D Kelly O’Day, writes on ProcessingTrends.com explains: “To facilitate assessments of long term trends, climatologists compare the mean for a base period with the annual mean. Differences between the annual mean and baseline mean are called anomalies. GISS uses the 1951 - 1980 period for their baseline period. They use the difference between the annual mean and the baseline mean to determine the global temperature anomaly for the year.”
O’Day produced a chart showing global temperature anomalies between 1800 and 2006 using data from NASA. I updated the chart he provided to include recently updated data up to 2011:
In the 1880 - 1935 period, the temperature anomaly was consistently negative. In contrast, the since 1980 the anomaly has been consistently positive. The 1917 temperature anomaly (-0.47oC) was the lowest year on record. Since 1917, global temperature has warmed, with the most recent years showing the highest anomalies of +0.6 oC in the past 120 years.Doesn’t Recent Record Cold Weather Disprove Global Warming?
In different parts of the world, there have been various weather events that at first thought would question global warming. For example, some regions have experienced extremely cold winters (sometimes record-breaking), while others have experienced heavy rain, etc.
The confusion that sometimes arises is the difference between climate change and weather patterns. Weather patterns describe short term events, while climate change is a longer process that affects the weather. A warming planet is actually consistent with increasing cold, increasing rain and other extremes, as an overall warmer planet changes weather patterns everywhere at all times of the year.
To get an idea of how looking at short term changes only can lead to a conclusion that global warming has stopped, or doesn’t exist, see Alden Griffith’s has global warming stopped?
(As an aside, those crying foul of global warming claims when going through extremely cold weather in Europe for example in 2010, later found their summers to be full of heat waves. The point