We all know smoking causes cancer.

It's common knowledge today, but we used to think that most cigarettes were fine.

Surprisingly, some of the first people to learn about tobacco's health impacts were tobacco companies themselves, but they kept this information from their customers for decades, and eventually got sued over it big-time.

Today, lawsuits are positioning climate change as this generation's smoking: it pollutes the air, it’s caused by burning chemicals we buy from a handful of huge companies, and it’s dangerous to human health.

Fossil fuel companies are being taken to court just like tobacco companies were, because of what they knew and when.

Should they be forced to pay for damages from climate change?

And can you even sue specific companies when we’ve all benefited from the industrialization that oil and coal made possible?

Hey, I’m Talia.

In 1983, after a lifetime of smoking and a lung removal, 57-year-old Rose Cipollone hired a lawyer to sue the tobacco company she blamed for her health problems.

The claim?

Tobacco companies knew that smoking was addictive and was linked to lung cancer, but didn’t share that information with the public.

The courts determined that the company was on the hook for misleading marketing that had described cigarettes with terms like “light,” and “low tar”.

There were even ads where doctors endorsed smoking.

But they found Rose was partly at fault too, because she chose to smoke.

Rose was awarded a $400,000 settlement ...after she died.

A wave of lawsuits followed, where states sued tobacco companies to pay back the costs for treating illnesses caused by smoking.

While all these legal battles were going on, leaked documents made it clear that tobacco companies had known their products were addictive and harmful, and had misled the public with their advertising and marketing.

In the late-90s, a massive settlement led to the companies paying 206 billion dollars in costs to dozens of states.

A new wave of legal action over climate change is drawing on the strategies from these old tobacco suits.

Documents unearthed over the last few years have shown that oil companies knew about climate change and the risks posed by fossil fuels, but concealed this information from the public for decades.

For instance, in a sampling of internal documents from ExxonMobil dating from between 1977 and 2014, 80 percent indicated that climate change was real and human-caused, even as 80 percent of their ads and editorials were casting doubt.

For cities, though, there’s little room for doubt.

San Francisco, like many coastal hubs, faces risks from rising seas caused by climate change, like damage to coastal infrastructure.

And climate change will also imperil their summer water supplies, local agriculture, tourism, and fishing industries.

In late 2017, San Francisco and Oakland sued the five largest oil companies asking that the corporations pay for infrastructure upgrades necessary to adapt to climate change, things like seawalls and raised buildings.

Their basis was that oil companies created a public nuisance -- a crime against everybody -- when they mined and marketed fossil fuels.

But so far, the courts aren't looking at climate change lawsuits with the same lens as tobacco lawsuits.

They recently dismissed this and other cases brought by cities against oil companies… but judges aren’t disputing climate science.

The courts said that since we have all benefited from the advantages of fossil fuels, the companies that sold them to us should not bear sole responsibility.

Instead, the judges ruled that any funding to deal with the effects of climate change should come from the federal government, and not a court settlement.

After all, regulating emissions and dealing with the risks from climate impacts has traditionally been the purview of federal agencies and international treaties.

The legal battles over climate change are far from over.

In July 2018, Baltimore announced a suit against 26 fossil fuel companies in Maryland state court.

Why would they do that?

Well, it allowed the city to sue for a long list of negligence and liability claims they wouldn’t be able to make in federal court.

In Juliana vs the United States, 21 young plaintiffs are suing the US government, claiming that climate change is infringing on their Constitutional right to life, liberty and property.

That argument hinges on a legal principle called the “public trust doctrine”— an idea that the government is legally obligated to protect shared natural resources like air, water, and wildlife.

And since the government has allowed and supported fossil fuel extraction on US lands and their burning, they’ve failed in this obligation.

For now, it seems that state and federal courts haven't quite decided whether climate change is within their jurisdiction.

It’s still too early to determine whether or not these climate lawsuits will work.

Tobacco cases dragged on for decades before being settled, and we’re just at the beginning of this legal road.

And, how would you even compensate the world for permanently raising the temperature?

Would everyone get cash to move away from eroding coastlines or to pay for medical costs from climate-induced illnesses?

There are also questions about whether only oil companies pay or if others should be on the hook, too -- like car manufacturers -- since their products contribute to the problem as well.

And then there's the fact that we all continue to use fossil fuels, despite knowing about their harms.

How do we deal with being partly at fault?

These are big questions and there are no easy answers.

Turns out, this climate change thing is complicated -- even judges will have a hard time figuring