Your Climate Change Questions, Answered

Questions

How do we know the planet is warming?

Icebergs float in the sea

Icebergs float in the Jokulsarlon glacial lagoon in Iceland.The glacier that feeds this lagoon is retreating rapidly.

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Global temperature measurements began in the 1880s. When we look at this data, there’s a clear increase in temperature—especially since the 1970s. Other signs point to a warming climate, like decreasing ice- and snow-cover, a rising sea level, impacts on vegetation, and changing animal migrations. These indicators span the planet; the signs of climate change are everywhere.

How do we know humans are responsible for the change in climate?

Ever since the Industrial Revolution of the 1800s, humans have been burning fossil fuels. We know that burning fossil fuels releases greenhouse gases like carbon dioxide and that these gases trap heat in our atmosphere and warm the planet.

Railroad tanker cars full of crude oil

Railroad tanker cars full of crude oil sit outside the Paulsboro Refining Company in New Jersey.

Luke Sharrett / Bloomberg / Getty

The concentration of greenhouse gases today is the highest it’s been for at least the past several hundred thousand years. Climate models—mathematical algorithms that use data to calculate past and future climate conditions—can’t reproduce our current climate based on natural indicators alone. Only when they account for these human-produced greenhouse gases do they correctly replicate our current global climate.

What can regular citizens do to help stop climate change?

Bike commuters cross a bridge in New York City.

Bike commuters cross a bridge in New York City. Driving less often is one way to reduce your personal impact on the climate.

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There’s a lot we can do, both as individuals and as members of a democracy.

First of all, we can all take a look at our own consumer choices and work to cut down our individual greenhouse gas footprint. Individual action can come in many forms: we can save energy at home, throw out less food, and use climate-friendly travel methods whenever we can.

Most importantly, as citizens and community members, we can put pressure on our elected officials to adopt clean energy policies that reduce carbon pollution and protect public health. There are many ways to make our voices heard. Read more about what you can do here.

Why is climate change so political?

Many Americans believe that taking action on climate change—or even believing in its existence—is a partisan issue. But that wasn’t always the case. In fact, the Environmental Protection Agency was started under President Nixon, a conservative Republican. The Clean Air Act of 1970 passed without a single “no” vote from a Democrat or a Republican. Many Republican leaders—including George W. Bush, Mitt Romney, Sarah Palin, and John McCain—have publicly supported climate action in the past.

Bipartisan climate change commercial

But in more recent years, the issue has grown increasingly political, even as more Americans agree that human-caused climate change is a real threat that requires action at all levels. The reason? Powerful campaigns, first by the oil industry, and more recently by coal industry-funded groups like Americans for Prosperity, have poured money into dividing Americans on what should be a bipartisan issue.

But voters are not as divided on this issue as politicians. Polls show that a wide majority of Americans—Republicans and Democrats alike—think that the United States should participate in international efforts to stop climate change. It’s just a matter of getting our politicians to represent our beliefs.

Demonstrators march near the White House

Demonstrators march near the White House on April 29, 2017. People came out to protest President Donald Trump’s attacks on climate policies.

Astrid Riecken / Getty

Did climate change cause the extreme weather we’ve seen recently?

Aerial view of hurricane damage in Puerto Rico

Hurricane Maria devastated Puerto Rico. Infrastructure damage was widespread, and huge swathes of the island were left without electricity or fresh water.

Ricardo Arduengo / AFP / Getty

2017 was a year of extreme weather. Hurricanes Harvey, Maria, and Irma caused extensive and ongoing damage to the American South and Caribbean. Wildfires burned nearly 10 million acres of land in the United States. It’s impossible to determine exactly what effect global climate change has had on a specific climate event. But we do know that a warming climate corresponds with stronger storms. “Attribution studies,” which assess how much climate change affects the likelihood and intensity of extreme weather events, are ongoing as scientists work to better understand—and predict—these devastating storms.

Why is the sea level rising, and why does it matter?

Flooding in the village of Eita, Kiribati

A resident of the village of Eita in Kiribati watches the ocean flood his hometown.  The island lies only a few feet above sea level, putting it at risk for flooding and sea swells.

Jonas Gratzer / Getty 

As the planet warms, the oceans rise. Melting ice sheets and glaciers are adding water to the oceans, and water expands when heated. Recent estimates suggest about a three-foot global sea level rise is likely within a century. Though it may not seem like a huge increase, three feet would give us the highest sea level in many thousands of years. It would severely impact coastal communities, which include half of the world’s most populous cities. Some low-lying islands would be submerged in the ocean. By the year 2100, around 2 billion people could be displaced due to rising sea level.

What is being done to stop climate change?

demonstrators gather in Paris

Hundreds of demonstrators gather in Paris for the opening of the 2017 One Planet Summit.

Michel Stoupak / NurPhoto / Getty Images

The biggest international effort to curb climate change is the Paris Climate Accord. It was negotiated during a series of United Nations conferences and has since been signed by every country in the world. In 2017, U.S. President Donald Trump announced that the United States would withdraw from the agreement. But despite this announcement, many U.S. cities, states, and companies have stepped up to help meet the Paris goals. A new initiative, called “We Are Still In,” has local leaders across the U.S. organizing in support of climate action. Though international action is essential to countering climate change, action on every level has an impact.

How certain is the scientific community that human-caused climate change is real?

A scientist in Cape Tribulation, Australia

A scientist in Cape Tribulation, Australia monitors climate change.

Phil Walter / Getty

In a word, very. A commonly cited figure is that around 97% of climate scientists agree that human activity is causing the planet to warm. If only natural forces were driving climate change, we would see either much slower warming or a cooling trend; human activity is the only explanation. Climate scientists are still debating and studying the details of how human-caused climate change will unfold—but they don’t doubt its existence. For example, will clouds amplify or moderate the warming trend?  How will jet streams differ in the future? How quickly will sea levels rise? There is much left to discover about the specific impacts of human-caused climate change—but the direction or cause of global warming is not in question.

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This content was developed in collaboration with the University of Wisconsin, Center for Climatic Research, Nelson Institute for Environmental Studies.