It is quite clear to me, based on my research, that tropical(热带的) insects rather than polar bears could be among the first species to become extinct(灭绝的) as a result of global warming.
Insects in the tropics are already living at the limit of their temperature range and any further increase could quickly kill them off. This would be a major disaster for tropical habitats, which rely on insects for everything from pollination(授粉) to waste disposal(处理). We have found that a rise in average temperatures in the tropics of just 1℃ or 2℃ could be enough to bring about a significant and harmful effect on the survival of a wide variety of important insects. Fitness levels most likely decline quickly and there may not be much we can do about it.
Many tropical species can only accept a narrow range of temperatures because the climate they experience is pretty steady throughout the year. Now our study shows that they will be harmed by rising temperatures more than species in cold climates. Unfortunately, the tropics also hold the large majority of species on the planet.
We used daily and monthly global temperatures from the 50-year period between 1950 and 2000and compared them with data showing the "fitness levels" of different species. "Fitness" was determined by indicators such as population growth rates and physical performance for different creatures.
We found that even moving into the shade did not help the insects. The direct effects of climate change on the organisms(生物) we studied appear to depend a lot more on the organisms' flexibility than on the amount of warming in the area where they lived.
As well as the danger to insects, the research confirms that there will be other consequences of global warming that could also have a serious impact on tropical regions, particularly on food crops. Our research focused only on the impact of changes in temperature, but warming will also change rainfall patterns. These changes could be more important for many tropical organisms, such as plants, but they are harder to predict.
