The climate where you live is called regional climate. Global climate is a description of the climate of a planet as a whole, with all the regional differences averaged.
Why Earth Is Warming
For over more than a century, the global average temperature has warmed. Learn the science of why this has happened, and what the future holds.
The Greenhouse Effect
Without the greenhouse effect, Earth’s temperature would be below freezing. It is, in part, a natural process. However, Earth’s greenhouse effect is getting stronger as we add greenhouse gases to the atmosphere. That is warming the climate of our planet.
Screenshot of the History of Climate Science page as a teaser image
How has our knowledge about Earth's climate grown over time? Use our interactive timeline to explore important and interesting scientific milestones, including when carbon dioxide was first discovered and when we learned about the heat-trapping ability of gases.
Why Does Climate Change?
Factors that have the power to change global climate can be natural, like volcanic eruptions and changes in solar energy, or caused by humans, like the addition of greenhouse gases to the atmosphere.
The Biosphere: An Integral Part of the Planet and its Climate
The biosphere is all life on our planet. Interdisciplinary research combining biochemistry, geochemistry, biology, hydrology, and atmospheric science helps us to better understand the biosphere’s role in the Earth system and, in particular, how biogeochemical cycles affect the Earth system.
El Nino
Learn how the El Niño-Southern Oscillation (ENSO) climate fluctuation affects weather around the world.
Climate Variability
Climate is the long-term average of the variable patterns of weather. Climate, however, can vary over time as well.
Coal being mined at a strip mine.
How has the geosphere impacted Earth’s climate? Typically, the geosphere reacts on geologic timescales, affecting climate slowly and over millions of years. However, the burning of fossil fuels over the last 150 years has sped the impact of the geosphere on climate.
Indirect Evidence of Climate Change
Both direct and indirect measurements are important for understanding the true scale of climate change. Learn how scientists use indirect evidence to study both modern and past climate change.
Tree rings in cross section

In order to predict our future climate, it's helpful to understand how and why the climate has changed in the past. Scientists use different types of clues to study the myriad ways that Earth's climate has changed during the past 4.6 billion years, including direct measurements, historical accounts, and paleoclimate proxy data, which are evidence of past climate preserved in fossils, sediments, ice and other places.

Spruce trees grow best in the chilly climate of a place like Alaska. Coconut palms thrive in the heat and humidity of a place like Panama.

Plants that have specific requirements for temperature and moisture can tell us about the climate of the region where they are found. As climates change over time, so do the plant species that are able to grow in a specific place. Knowing what plants used to be able to grow in a place can tell us what the climate was like in the past.

Researching Climate Change

Climate change research involves numerous disciplines of Earth system science as well as technology, engineering, and programming. Some major areas of climate change research include water, energy, ecosystems, air quality, solar physics, glaciology, human health, wildfires, and land use.

global energy flows diagram
Accounting for all the energy that enters and leaves the Earth system helps us understand why the planet is warming. This accounting of energy is known as Earth’s radiation budget.
Climate images

Photos, diagrams, and other images related to climate and climate change.

Climate videos

Short video clips about climate - including paleoclimates, climate change and modeling climate.

Climate game and simulations
Test your knowledge with one of our games or gain a deeper understanding of climate through a simulation.
How Climate Works Activities
From activities about evidence of climate change, to inquiries into current and future impacts, and explorations of the role of energy use in current climate warming.