EPA’s 2016 assessment of climate change indicators in the U.S. showed that the Earth’s climate is changing. Rising temperatures, shifting snow and rainfall patterns, and more extreme climate events like heavy rainstorms and record-high temperatures were already taking place.
EPA has issued its latest assessment of climate change indicators in the U.S.
The Earth’s climate is changing. Temperatures are rising, snow and rainfall patterns are shifting, and more extreme climate events—like heavy rainstorms and record-high temperatures—are already taking place. Scientists are highly confident that many of these observed changes can be linked to the levels of carbon dioxide and other greenhouse gases in our atmosphere, which have increased because of human activities.
HOW IS THE CLIMATE CHANGING?
Since the Industrial Revolution began in the 1700s, people have added a significant
amount of greenhouse gases into the atmosphere, largely by burning fossil fuels to
generate electricity, heat and cool buildings, and power vehicles—as well as by clearing
forests. The major greenhouse gases that people have added to the atmosphere
are carbon dioxide, methane, nitrous oxide, and fluorinated gases. When these gases
are emitted into the atmosphere, many remain there for long time periods, ranging
from a decade to thousands of years. Past emissions affect our atmosphere in the
present day; current and future emissions will continue to increase the levels of these
gases in our atmosphere for the foreseeable future.
“Greenhouse gases” got their name because they trap heat (energy) like a greenhouse
in the lower part of the atmosphere (see “The Greenhouse Effect” below). As
more of these gases are added to the atmosphere, more heat is trapped. This extra
heat leads to higher air temperatures near the Earth’s surface, alters weather patterns,
and raises the temperature of the oceans.
These observed changes affect people and the environment in important ways. For
example, sea levels are rising, glaciers are melting, and plant and animal life cycles
are changing. These types of changes can bring about fundamental disruptions in
ecosystems, affecting plant and animal populations, communities, and biodiversity.
Such changes can also affect people’s health and quality of life, including where people
can live, what kinds of crops are most viable, what kinds of businesses can thrive
in certain areas, and the condition of buildings and infrastructure. Some of these
changes may be beneficial to certain people and places, as indicators like Length of
Growing Season point out. Over time, though, many more of these changes will have
negative consequences for people and society