Long-term shifts in Earth's climate system
Climate change
Climate change refers to sustained changes in temperature, rainfall, oceans, ice, and extreme weather patterns, driven today largely by human greenhouse gas emissions and their effects on the atmosphere, land, and sea.
What climate change means
Climate is the long-term pattern of weather in a region or on the planet as a whole. Climate change means those patterns are shifting over time. The modern conversation usually refers to human-caused warming from greenhouse gases, but the term also covers changes in rainfall, storms, ocean conditions, and ice cover.
Why the planet is warming
When carbon dioxide, methane, and other greenhouse gases build up in the atmosphere, they trap more heat and reduce how quickly Earth can release energy back to space. Burning fossil fuels, deforestation, and some industrial processes have increased these gases dramatically since the Industrial Revolution.
What is changing
Rising global temperatures are linked to melting glaciers and ice sheets, shrinking sea ice, warming oceans, sea-level rise, more intense heat waves, heavier rainfall in some places, longer droughts in others, and changing ecosystems. Not every region changes in the same way, but the overall pattern is clear in the data.
Why oceans matter
The oceans absorb much of the excess heat and a large share of the carbon dioxide humans emit. That makes them central to the climate system, but it also means they are changing in ways that affect marine life, coastal communities, and weather patterns. Ocean warming and acidification are major parts of the story.
What adaptation and mitigation mean
Mitigation means reducing the causes of climate change, mainly by cutting greenhouse gas emissions and protecting natural carbon stores. Adaptation means adjusting human systems and infrastructure to the changes already underway, such as stronger heat planning, flood protection, crop changes, and water management.
Why it matters
Climate change matters because it touches food, health, water, infrastructure, migration, economies, ecosystems, and security. It is not only an environmental issue but also a human one, since the costs and risks are unevenly distributed and can grow quickly as warming increases.