As President Obama tours the Arctic to raise awareness about global warming, we’re getting new evidence about just how dire a situation our planet is in.

In preparation for this fall’s big climate talks in Paris, 56 countries have come out with their own national targets for cutting greenhouse gasses.

And while a bunch of countries getting together and taking action against CO2 emissions certainly sounds like a good thing, there’s a catch.

According to new data from the Climate Action Tracker, the targets those 56 countries have come out with would result in an atmospheric temperature rise of 3.1 degrees Celsius above pre-Industrial levels by the end of the century.

Since the official goal of this year’s climate talks is to prevent warming from exceeding the very dangerous level of 2 degrees Celsius, this means that the current national targets are, well, inadequate, to say the least.

That’s a really big deal.

After we cross the 2 degrees Celsius tipping point, global warming will lock in with devastating consequences for every single living thing on this planet.

This could happen as soon as a few decades.

Michael Mann, a frequent guest on this program and one of the world’s leading climate scientists, estimates that we only have until 2036 -- 21 years -- to prevent the Earth’s temperature from warming to 2 degrees above where it was before we started using fossil fuels.

And here’s the thing, even that 2 degree Celsius benchmark might be not be enough to hold off environmental devastation on a scale we haven’t seen in millennia.

Two degrees Celsius warming is what the world’s climate negotiators have decided is “possible” and “acceptable,” but according to former NASA scientists James Hansen, even that little warming is a recipe for disaster.

He explained why in a recent interview with Australian radio.

Hansen now says we have to limit ourselves to 1 degrees Celsius warming - a number we’re already dangerously close to reaching.

So time really is running out to save the planet.

At this point, there's really only one thing we can do to prevent a total climate catastrophe: we must keep carbon in the ground.

And the best way to keep carbon in the ground is to put a price on it.

Right now, the fossil fuel industry is the only industry in the world that doesn’t have to pay to clean up its own waste.

Instead, these guys pass the costs of that waste (carbon pollution) on to the rest of us in the form of what economists call "negative externalities.”

Some examples of “negative externalities” include things like the cost of cleaning up from climate-change-driven severe weather events, the cost of pollution-related health problems, and the cost to local economies of fishing grounds devastated by ocean acidification.

Because the fossil fuel fat-cats like Exxon and the Kochs just pass the costs of these externalities on to you and me to pay the bill, while getting an estimated $5.3 trillion in subsidies every year, the fossil fuel industry is artificially profitable and artificially competitive.

Oil and gas are only cheaper than wind and solar because their market price doesn’t reflect the damage they do to our planet and our society.

But if their market price did take into account this damage, then the fossil fuel industry would immediately lose out to renewables that are actually much, much cheaper than gas, coal, or oil.

Which is why President Obama or his successor should put propose a national carbon tax and make the fossil fuel industry and billionaires pay to dispose of their own trash.

Even a small $10-per-ton national carbon tax would cut greenhouse gas emissions by around 28 percent of 2005 levels, save tens of thousands of lives, and, if the proceeds were given back to We The People like Alaska’s permanent fund, could help jump-start the renewable energy industry.

This isn’t complicated.

It’s economics 101.

So if President Obama really wants to beef up his climate legacy, he should do more than just visit some melting glaciers in Alaska.

He should start working right now on the one thing that will really take the fight Big Oil: a national carbon tax.