Beyond the environmental implications of a warmer planet, scientists now believe that increases in carbon dioxide levels and temperatures may lead to smaller lifeforms.
A new report published by researchers confirms that 55 million years ago, something very similar happened. During this period, called the Paleocene-Eocene Thermal Maximum, carbon dioxide levels in the atmosphere spiked. Theories for the rise range from volcanic activity to comet impacts to a massive release of methane.
The study found that soil-inhabiting creatures decreased in body size by nearly half in response to atmospheric warming. It was already well known that mammals were reduced by almost 50 percent -- but this new information confirms the effects of global warming on those underground as well.
Along with a decrease in size, the researchers also found shorter lifespans associated with the insects -- distant relatives of modern ants, cicadas, dung beetles, earthworms and crayfish.