Frequently Asked Questions About Climate Change
This page includes answers to some frequently asked questions about climate change. For information about evidence of climate change, the greenhouse effect, and the human role in climate change, please see EPA Climate Science.
- Terms
- Today’s Climate Change
Terms
What is climate change?
Climate change involves significant changes in average conditions—such as temperature, precipitation, wind patterns, and other aspects of climate—that occur over years, decades, centuries, or longer. Climate change involves longer-term trends, such as shifts toward warmer, wetter, or drier conditions. These trends can be caused by natural variability in climate over time, as well as human activities that add greenhouse gases to the atmosphere like burning fossil fuels for energy.
What is the difference between weather and climate?
"Weather" refers to the day-to-day state of the atmosphere such as the combination of temperature, humidity, rainfall, wind, and other factors. "Climate" describes the weather of a place averaged over a period of time, often 30 years or more.
The difference between weather and climate is largely defined by time and geography. Weather refers to the conditions of the atmosphere over a short period of time and typically for a local area. Climate refers to the behavior of the atmosphere over a longer period of time, and usually for a large area. Scientists can compare recent and long-term observations of the climate to detect the influence of greenhouse gases on climate conditions.
What is the difference between global warming and climate change?
The terms "global warming" and "climate change" are sometimes used interchangeably, but global warming is just one of the ways in which climate is affected by rising concentrations of greenhouse gases.
What is the difference between climate change and climate variability?
Climate change occurs over a long period of time, typically over decades or longer. In contrast, climate variability includes changes that occur within shorter timeframes, such as a month, season, or year. Climate variability explains the natural variability within the system. For example, one unusually cold or wet year followed by an unusually warm or dry year would not be considered a sign of climate change.
Today’s Climate Change
Do natural variations in climate contribute to today’s climate change?
The earth does go through natural cycles of warming and cooling caused by factors such as changes in the sun or volcanic activity. For example, there were times in the distant past when the earth was warmer than it is now.
Is climate change happening in the same way everywhere on the planet?
Although climate change is often referred to in global terms, different geographic regions are experiencing climate change in different ways. For example, some places, like the Arctic, are experiencing warming more rapidly than the rest of the world.1
Differences such as these are related to natural climate variations, which can occur because of differences in factors such as topography, ocean currents, and latitude. Differences in land use can also affect regional changes in climate. For example, urbanization and deforestation have both shown to exacerbate increasing temperatures.2
Why has my town experienced record-breaking cold and snowfall if the climate is warming?
Even though the planet is experiencing an overall average warming, some areas may be experiencing extra cold or snowy winters. These cold spells are due to variability in local weather patterns, which sometimes lead to colder-than-average seasons or even colder-than-average years at the local or regional level.
References
1 Constable et al. (2022). Cross-Chapter Paper 6: Polar Regions. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 2319–2368, doi:10.1017/9781009325844.023.
2 IPCC. (2019). Summary for Policymakers. In: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V. Masson-Delmotte, H.- O. Pörtner, D. C. Roberts, P. Zhai, R. Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. Huntley, K. Kissick, M. Belkacemi, J. Malley, (eds.)].