Alabama Landscapes

Climate Change

There is now no question that global climate change has occurred rapidly through the 20th century (Figure CC1.   Global temperatures rose 0.5-1.0°F (0.45-0.6°C) , much more rapidly than in the previous 9 centuries (Figure CC2).  Climate change has paralleled increases in greenhouse gases in the atmosphere.

Figure CC1.  Global annual temperature change  (EPA, http://yosemite.epa.gov/OAR/globalwarming.nsf/content/Climate.html)

Figure CC2.  Estimated annual gloal temperature changes, 1200-2000. (EPA, http://yosemite.epa.gov/oar/globalwarming.nsf/UniqueKeyLookup/SHSU5BWJE7/$File/wg1_science-sum.pdf)

Local climate changes do not necessarily parallel global changes.  Average annual temperatures recorded in Birmingham since 1930 (Figure CC4) show a cooling  from the 1930s to 1969 and then an increase.

Figure CC4.  Deviations of average annual temperatures from mean 1961-1990 at Birmingham. 

For the state as a whole, mean annual temperatures have changed little, but annual precipitation has increased by 10-20% (US National Assessment of Climate Change, 2000).