May 2021

The earth is getting warmer

This article is the third in a series focused on the causes and consequences of a warming planet

The earth is in a period of rapid warming. The last five years are the warmest on record. According to NASA, 2016 and 2020 were essentially tied for the warmest since records began in 1880. 2019 was the second warmest.

The planet’s average surface temperature has risen about two degrees Fahrenheit (slightly over one degree Celsius) since the late 19th century according to NASA and NOAA.

temperature anomaly chart

In addition to NASA and NOAA, the warming of the planet is confirmed by other organizations such as the Met Office of England, the Potsdam Institute of Germany, the Japanese Meteorological Society and Berkley Earth.

Further evidence of a warming planet is confirmed by several changes in the earth’s climate. For example, glaciers are melting, sea levels are rising, the oceans are warming, Arctic sea ice is disappearing, the land and sea surface is warming, snow cover is declining and wildlife and plant life are moving north. Each of these indicators are supported by multiple data sets.

The warming is not even across the planet. The Arctic is warming at least twice as fast as the rest of the planet. The air over land is warming faster than air over the oceans. In many regions, nights are warming faster than days and winters are warming faster than summers. Scientists have cause-effect evidence of why this is happening. In fact, all of these effects now being observed were predicted by the cause-effect climate model published in the early 1980s.

This amount of warming may not seem significant considering the variations in temperature we experience from day to day and season to season. But the average temperature of the earth has been surprisingly constant over the last 10,000 years. This constancy has allowed for the emergence of human civilization.

A small change in average temperature can cause significant changes in climate. For example, the earth’s average temperature during the last ice age, when huge ice sheets covered much of North America, was only about 10 to 12°F colder than it was at the beginning of the industrial revolution.

With strong economic growth and no efforts to curb greenhouse gas emissions, the rate of warming will remain strong or even increase. Under these conditions the temperature is estimated to have increased by about 8°F with a range of from 5.5 to 9.5°F from 1900 to 2100.

The speed of warming is also a concern. Rapid warming makes it difficult for life on earth to adapt.

It took thousands of years for the earth to move out of the ice age. By comparison, the projected 8°F increase by the end of the century described above will have occurred in only 200 years.

A listing of USDA and university websites focused on weather and climate can be found on the Ag Decision Maker Outlook page


Don Hofstrand, retired extension value added agriculture specialist, agdm@iastate.edu
Reviewed by Dr. Eugene Takle, retired professor emeritus Iowa State University

Author

Don Hofstrand

retired extension value added agriculture specialist
View more from this author
Reviewed by

Dr. Eugene Takle

retired professor emeritus Iowa State University