A remarkable new study claims that global warming will have a major effect on humans in the future in one key way: it will shrink us. A new study claims that major warming events results in dwarfism in mammals, and even shorter periods of warming can result in patterns of shrinkage.

Scientists examined one of the largest of the hyperthemal periods, the Paleocene-Eocene Thermal Maximum (PETM), and found that while temperatures rose between nine and 14 degrees Fahrenheit, mammals shrank by 30 percent. So they started looking at other warming events to see if the trend holds.

By examining the molar teeth to gauge body size on ancient bones dated from different warming periods, researchers determined that two species they examined shrank 14 and 15 percent. Why does this happen? Scientists think it may be possible that CO2 levels diminished the nutrients in plant, and stunting the mammals’ growth.

“We know that during the largest of these hyperthermals, known as the Paleocene-Eocene Thermal Maximum, or PETM, temperatures rose an estimated nine to 14 degrees Fahrenheit and some mammals shrank by 30 percent over time, so we wanted to see if this pattern repeated during other warming events,” says Abigail D’Ambrosia, a doctoral student at UNH and lead author of the study. “The hope is that it would help us learn more about the possible effects of today’s global warming.”