General questions

  • What’s the difference between climate change and global warming?

    “Global warming” refers to the long-term warming of the planet. “Climate change” encompasses global warming, but refers to the broader range of changes that are happening to our planet, including rising sea levels; shrinking mountain glaciers; accelerating ice melt in Greenland, Antarctica and the Arctic; and shifts in flower/plant blooming times.

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  • What’s the difference between weather and climate?

    “Weather” refers to the more local changes in the climate we see around us, on short timescales from minutes to hours, to days to weeks. Examples are familiar – rain, snow, clouds, winds, thunderstorms, sleet, and hail.

    “Climate” refers to longer-term averages (which may be regional or global) and can be thought of as the weather averaged over several decades.

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  • Is it too late to prevent climate change?

    Humans have caused major climate changes to happen already, and we have set in motion more changes still. However, if we stopped emitting greenhouse gases today, the rise in global temperatures would begin to flatten within a few years. Temperatures would then plateau but remain well-elevated for many, many centuries.

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  • Do scientists agree on climate change?

    Yes, the vast majority of actively publishing climate scientists – 97 percent – agree that humans are causing global warming and climate change.

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  • What’s NASA got to do with climate change?

    NASA’s role is to make observations of our Earth's systems (geosphere, biosphere, cryosphere, hydrosphere, and atmosphere)--and how they connect--that can be used by the public, researchers, policymakers and to support strategic decisions. Its job is to perform rigorous science. However, the agency does not promote particular climate policies.

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Climate data


Greenhouse gases


Global temperatures (land and ocean)


Ice and snow


The sun, volcanoes, and more


Past climates

  • How do we know what greenhouse gas and temperature levels were in the distant past?

    Ice cores are scientists’ best source for historical climate data. Other tools for learning about Earth’s ancient atmosphere include growth rings in trees, which keep a rough record of each growing season’s temperature, moisture and cloudiness going back about 2,000 years. Corals also form growth rings that provide information about temperature and nutrients in the tropical ocean. Other proxies, such as benthic cores, extend our knowledge of past climate back about a billion years.

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