Species and global climate change

Article By:

Comiso, Josefino C. Cryospheric Sciences Branch, Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, Maryland.

Last reviewed:2009

DOI:https://doi.org/10.1036/1097-8542.YB090082

Observations started by Charles Keeling at Manoa Loa, Hawaii, in the 1950s provided the indisputable evidence that anthropogenic carbon dioxide in the atmosphere has been increasing at an alarming rate. The current level is more than 380 parts per million by volume, which is already much higher than the natural range of 180 to 300 ppm in the past 650,000 years as recorded by ice cores. Carbon dioxide is a greenhouse gas, which, according to earlier calculations by Svante Arrhenius in the 1890s and confirmed by current numerical models, can cause a warming of our planet. Other greenhouse gases such as methane and nitric oxide have also been increasing, further exacerbating the problem. Meanwhile, since the beginning of the twentieth century, the surface air temperature of the Earth as measured by meteorological stations has increased by about 0.7°C (1.2°F). The data also show that the rate of increase in the last 50 years has been twice as great as the rate in the last 100 years, with the 10 warmest years on record occurring since 1995. Among the key issues associated with global warming is the fate of millions of species that inhabit the Earth. Warming disrupts and alters the ecosystems and therefore the diversity of plant and animal species in the systems. In this regard, the polar regions have been the center of attention, because climate signals in these regions are expected to be amplified by as much as three to five times as a result of ice–albedo feedbacks. (Albedo is the fraction of solar energy reflected by a surface. In ice–albedo feedback loops, melting ice resulting from warmer temperatures causes a lowering of the albedo, which leads to even more ice melting.)

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