Climate has always varied over time -- on average, some years, decades, centuries, or even millennia have been colder or warmer, wetter or drier through history. But scientists everywhere agree that the climate has been rapidly warming over the last 100 years, which has disrupted climate patterns around the planet. And there is broad consensus that these changes are being caused by human activity, mainly burning fossil fuels for energy. 

Why is the climate changing?

Global climate change refers to the rapidly changing climate patterns we see all around the world. The main cause of climate change is excess levels of greenhouse gases that humans have been putting into the atmosphere since the Industrial Revolution. Increasing carbon dioxide is mainly coming from burning fossil fuels for energy. Methane and nitrous oxide are mainly coming from industrial agriculture.

Where is the evidence?

Thousands of scientists around the world have been studying our global climate and collecting data for many years so they could examine long term trends. The videos below provide visualizations of just a few of the data sets that offer evidence of our rapidly changing climate, and its root cause in human activity.

Global Warming from 1880 to 2021

This visualization illustrates Earth’s global average surface temperature from 1880-2021.

Source: NASA

Climate Spiral

This visualization shows monthly global temperature anomalies (changes from an average) between the years 1880 and 2021. Whites and blues indicate cooler temperatures, while oranges and reds show warmer temperatures.

Source: NASA

Atmospheric CO2 

This visualization illustrates the history of atmospheric carbon dioxide from 800,000 years ago until the end of the most recent data collection (2021).

Source: NOAA

Annual Arctic Ice Minimum

Satellites have provided a reliable tool for continuously monitoring changes in the Arctic ice since 1979. Every summer, the Arctic ice cap melts to what scientists call its "minimum" before colder weather begins to make ice cover increase. This visualization shows the expanse of the annual minimum Arctic sea ice for each year from 1979 through 2022, with a graph overlay.

Source: NASA

Effects of climate change

A changing climate is having all sorts of troubling affects for life on earth. Major storms and weather events are happening more frequently. Droughts and floods are occurring. We are seeing hotter summers and erratic temperatures, which is making it more difficult to grow food crops in some parts of the world. Polar ice is melting into the sea, which is causing sea levels to rise and marine systems to change. 

All of these impacts affect life on Earth, and some communities are feeling the effects more than others.