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Climate Change: The Science

There’s no more debating if climate change is a reality. Scientists agree: the world is getting warmer and human activity is largely responsible. Today, our planet is hotter than it has been in 2,000 years, and on track to grower hotter than it’s been in two million years.

© Greenpeace / Daniel Beltrá

The latest IPCC report states “It is unequivocal that human influence has warmed the atmosphere, ocean and land.” Today, our planet is hotter than it has been in 2,000 years, and on track to grow hotter than it has been in two million years.

For the oil and gas industry, delay and distraction are the new denial. Companies like Exxon, Chevron, Shell, and BP spent decades sowing doubt about the science of climate change. Now in the face of widespread public support for climate action, they’re distorting the facts about their role in the climate crisis and falsely casting themselves as allies. Politicians in the pocket of the industry have mirrored their delay and deny tactics to further confuse the public. But climate change is no mystery. Understanding science can tell us a lot about the causes and effects of our warming world.

What We Know

Years of scientific investigation have given us a clear understanding of what’s causing climate change and how humans are contributing. It works like this:

  • Certain gases in the atmosphere — most importantly carbon dioxide — create what’s called the greenhouse effect, trapping in heat and regulating the Earth’s temperature.
  • Burning fossil fuels releases more greenhouse gases into the atmosphere, particularly carbon dioxide which is the main driver of anthropogenic warming.
  • Every tonne of CO₂ emissions adds to global warming and the temperature rise is proportional to cumulative CO2 emissions.
  • There’s more carbon dioxide in our atmosphere now than there’s been in the past 2 million years.

We’re also learning more about the impacts of climate change, many of which have serious consequences for humans and wildlife:

  • Climate change is closely linked with the rise in extreme weather events we’ve experienced in recent years. Hurricanes, typhoons, wildfires, floods and drought are all made worse by climate change. Our 50 States in Climate Crisis map shows how your state could be affected.
  • Melting polar ice caused by warmer temperatures has huge ripple effects. Not only does it threaten the habitat of species like polar bears and penguins, with potentially devastating impacts for the cultural survival of Indigenous Peoples, it is one of the causes behind rising sea levels which threaten coastal cities and communities.

How We’re Changing the Climate

Global temperatures have risen and fallen over the Earth’s history for natural reasons. What’s unique about the warming we’re experiencing now is that it can’t be explained by those natural reasons, and that it’s happening faster than ever before.

Human activity plays a central role. The fossil fuels we burn to power our homes, businesses, and cars all release carbon dioxide and other potent pollutants into the atmosphere. Deforestation for timber and agriculture is another major source of greenhouse gas emissions.

Humans are at the center of the problem, but this also means the power is in our hands. The choices we make today, and the people power we build together, will determine the future of our planet.

Still need more information? Don’t just take it from us. 97% of scientific papers agree that the Earth’s temperature is rising and human activity plays a central role — and NASA has compiled the studies to prove it. Another group of researchers found that the scientific consensus on human-caused climate change is over 99% in peer reviewed scientific literature.

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