Page 116 - Universal

hunt for seals. As ice melts, they either end up on land or must swim farther from shore
to find ice, which hurts their ability to find food and leads to long periods of fasting that
deplete fat reserves. Human-caused global warming means there are fewer days of sea ice

to help build up those reserves and longer fasting periods, and scientists have said most
polar bears could become extinct by the end of the century unless warming is curbed.

A 2020 study found the number of fasting days, determined by the number of ice-free
days every summer, directly affected cub survival. The new study, took a step further and
quantified the number of ice-free, fasting days caused by a specific amount of human-
caused greenhouse gas emissions — distinct from what’s already in the atmosphere.

“What’s really relevant for policy is emissions,” rather than atmospheric concentrations,
said co-author Cecilia M. Bitz, a climatologist and director of the climate change program

at the University of Washington.

Researchers estimated the relationship between how long bears fasted and each gigaton of
cumulative emissions, which they said allowed them to calculate the impact of emissions
from specific projects on future polar bear cub survival.

“It’s basically connecting the dots from emissions to ice-free days to impacts on polar
bears,” said Amstrup, who believes the method can be applied to many other species,
such as sea turtles or coral reefs. He also believes the study makes a case for rescinding

the 2008 opinion barring climate considerations because the Endangered Species Act
requires federal agencies to use the best available scientific data.

–Newspaper Article

Word Meanings

emissions the release or discharge of substances, especially gases or

pollutants, into the atmosphere

conservation the act of preserving, protecting, or managing natural resources

endemic native or restricted to a particular geographic area or region
and not naturally found elsewhere

granivores animals that primarily feed on seeds, such as grain-eating birds

habitat the natural environment or surroundings in which a particular
species or organism lives

carnivores animals that primarily eat other animals, flesh, or meat as their
main food source

114