Atmosphere Journal Entry
Global Warming Threatens Species (January 17, 2004)
NASA surface temperature map shows how global temperatures varied from long-term averages between 1951 and 2002. Areas in yellow warmed 0.2 to 0.5 degrees Celsius. Temperatures in light-brown areas rose by 0.5 to 1.0 degrees, brown areas by 1 to 2 degrees, and red areas by 2 to 4 degrees. Notice that very few areas cooled (shown in blue). NASA GISS.
Global warming threatens more than a million species of plants and animals, according to a new study by scientists from Conservation International. The researchers say nearly one-fourth of all the species on the planet may vanish over the next fifty years if global temperatures keep rising at their current rate.
The scientists say the biggest problem is that species have nowhere to go if their habitat becomes unsuitable because of rising temperatures. Even small temperature changes will force animals to move to a cooler part of their range. But if their path is blocked because of human development or habitat destruction, they have nowhere to go.
Plant species will suffer as well. More and more plants will become endangered by stress from lower soil moisture levels and higher temperatures. This in turn would affect all the animals that depend on them for food or shelter.
The researchers looked at the possible impacts of three different climate change scenarios. They compared small, medium, and large global temperature changes. In the medium scenario, global temperatures would rise by about 3 degrees Fahrenheit through 2050. In that scenario, computer models predict that 1.25 million species will become extinct.
The situation gets even worse in the maximum (greater than 3.6 degrees Fahrenheit) temperature rise scenario. Overall, more than one-third of the world's species would be lost. In Queensland, Australia, 85% of birds would face extinction. In the Amazon Basin, 87% of all plant life would disappear.
The study was based on data of more than 1,000 animal and plant species in Brazil, South Africa, Mexico, Australia, and Europe. These areas represent about one-fifth of Earth's total landmass. Species in the dry forests of the Brazilian Cerrao would be hit particularly hard. Even in the scenario with the smallest temperature rise, two-thirds of the forest's plant life would be lost. The mammals of South Africa would also suffer greatly. In the medium scenario, nearly 70% of them would vanish.
The researchers say only immediate and drastic cuts in worldwide levels of carbon dioxide and other greenhouse gases will improve the situation. These gases act like a blanket in Earth's atmosphere that traps the Sun's heat in what is known as the greenhouse effect.
