Our editors will review what you’ve submitted and determine whether to revise the article.
Lower Troposphere: http:///data/msu//tlt/uahncdc_lt_
Lower Stratosphere: http:///data/msu//tls/uahncdc_ls_
31,487 American scientists have signed this petition, including 9,029 with PhDs For information about this project, click on the appropriate box below.
NASA’s Goddard Institute of Space Studies (GISS) tracks atmospheric global temperature climate trends. As environmental engineer, D Kelly O’Day, explained on (link no longer available): 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.
Projections suggest changes in the frequency and intensity of some extreme weather events.  Confidence in projections varies over time. 
Why has it been so difficult to achieve meaningful solutions to global warming? Media pundits, partisan think tanks, and special interest groups raise doubts about the truth of global warming. This barrage of misinformation misleads and confuses the public — and makes it more difficult to implement effective solutions.