Temperatures are Increasing
Concentrations of greenhouse gases were roughly constant for the last 10,000 years, until the industrial era began in the mid-1800’s. Now, greenhouse gas concentrations are rising rapidly. The current rates of temperature increases make it difficult for many species to evolve or migrate in response to today’s rapid environmental change, which involve not only temperature, but precipitation patterns, storm tracks, ice cover, and ocean chemistry.
CARBON DIOXIDE
Preindustrial Level: 280 parts per million
Current Level (mid-2010): 388 ppm
Increase since 1750: 108 ppm
METHANE
Preindustrial Level: 700 parts per billion
Current Level: 1745 ppb
Increase since 1750: 1045 ppb
NITROUS OXIDE
Preindustrial Level: 270 parts per billion
Current Level: 314 ppb
Increase since 1750: 44 ppb
DID YOU KNOW?
Water vapor is an important greenhouse gas. It is difficult to affect, or even measure global water vapor at a given moment in time. However, warmer air can hold more moisture than colder air, so a positive feedback occurs. When the air is warmed by the greenhouse effect of additional carbon dioxide, this enables more water to be held in the air, which adds to the warming, which then adds to the water, which produces further warming. As such, carbon dioxide can be considered a trigger of additional greenhouse warming by water vapor.