As Hurricane Michael barreled down on Florida, famed climate scientist Dr. James Hansen traveled to Minnesota earlier this week to testify on the imminent danger of climate change. He was supposed to be an expert witness at the trial for the “valve turners,” the anti-pipeline activists who staged an unprecedented coordinated action to shut down the flow of oil from Canada to the United States in 2016. But the judge ruled she would not allow witnesses like Dr. Hansen to testify on the clear and present danger posed by climate change. On Tuesday, valve turner activists Annette Klapstein and Emily Johnston were acquitted. We speak with Hansen in Minneapolis about the valve turners, the recent IPCC report about the imminent threat of climate change and what must be done to save the planet from destruction. Hansen is the former top climate scientist at NASA. He is now the director of Climate Science, Awareness and Solutions at Columbia University’s Earth Institute. We also speak with Klapstein and Johnston.

AMY GOODMAN: Dr. James Hansen is the former top climate scientist at NASA. From 1981 to 2013, he was the head of the NASA Goddard Institute for Space Studies, now the director of Climate Science, Awareness and Solutions at Columbia University’s Earth Institute. He traveled to Minnesota to testify at the trial for the valve turners, but the judge ruled she would not allow expert witnesses, like Dr. Hansen and 350.org founder Bill McKibben, to raise this issue—to testify at all or raise this issue about climate change and the connection to what the valve turners were doing. Dr. Hansen, why did you go to Minnesota, agree to testify in this case? Why did, the valve turners, you want to defend?

JAMES HANSEN: Well, of course, they’re trying to draw attention to the climate issue, and particularly to the egregious role of the tar sands. And I just was supposed to help explain the climate consequences of this carbon source.

AMY GOODMAN: And talk about the consequences, because, ultimately, of course, as the valve turners have said, this is why they’ve done what they’ve done. It’s this connection to climate change.

JAMES HANSEN: Yeah. Well, you know, the difficulty is the delayed response of the climate system and the fact that it includes amplifying feedback, so the public doesn’t see that much going on. The public does realize that climate is beginning to change, but it doesn’t have a good picture of the ultimate consequences of that, because they will be much greater in the lifetimes of our children and grandchildren. And we need to begin to move on a path of decreasing emissions very rapidly if we’re going to preserve the same planet that we’ve enjoyed, for our children and grandchildren. And that just has not been clear enough, I think, in the prior—in the public’s mind.

AMY GOODMAN: You know, it’s interesting that this trial came just as the United Nations climate scientists warned in a landmark report that humanity has only a dozen years to mitigate climate change or face global catastrophe. If you, Dr. Hansen, can talk about the significance of this report and, at the same time, this massive monster hurricane, Hurricane Michael, bearing down on the Florida Panhandle? It’s believed to be the worst Florida has seen in something like a century in this area, about to make landfall.

JAMES HANSEN: Yeah, well, I think this report is really a good report from IPCC, the Intergovernmental Panel on Climate Change. The prior reports do not always convey the urgency of the issue and really make it very clear to the public. But this one, I think, did a very good job, both in warning about the consequences if we don’t do something, and in making clear that we still can do something, but we have to begin very quickly to actually phase down emissions, while, in fact, emissions will continue to climb if we don’t have some significant policy changes.

AMY GOODMAN: I don’t know if you’re getting a chance to see the climate coverage of the hurricane—meteorologists, reporters down in the Panhandle warning, you know, people must leave, evacuate, and, of course, the politicians, as well. But there is almost no mention of climate change. Can you talk about that connection, the intensification of these hurricanes?

JAMES HANSEN: Yeah. Yeah, well, sure. If you look at the temperatures of the ocean in the Gulf and off the East Coast of the United States, they are way above normal. And, of course, as everyone knows, and I think even the public understands, if the ocean is warmer, that provides the fuel for these tropical storms. And that’s exactly what we’re seeing. That storm is intensifying because the water is unusually warm. And so we’re getting a very strong storm out of what would have been a weaker storm without that additional push from the extraordinarily warm ocean.

AMY GOODMAN: And the tsunami, the earthquake and tsunami that we saw in Indonesia in the island of Sulawesi, this horror, where it looks like 5,000 people are missing, 1,700 confirmed dead, is there any link there? If not the earthquake, the power of the tsunami?

JAMES HANSEN: Well, there’s a link in terms of the impact of the tsunami. There are recent papers on this that show that sea level is rising. And when you add the human-caused increase in sea level to the tsunami, it makes it more damaging. That has been actually apparent on the recent hurricanes hitting the United States. The sea level—global average sea level has gone up by 20 centimeters because of greenhouse warming, which is about 8 inches, but along the coast, eastern coast, of the United States, it’s about twice as much. And when you add that sea level rise to the storm surges, it makes them that much worse.

And, of course, the warming also increases the amount of water vapor in the atmosphere, increases the rainfall totals. And so, the global warming effect has been making hurricane effects significantly larger. There’s also a recent paper by James Kossin which argues that the speed, the translation speed of these storms, in many cases, has been slowed down, and that in the case of the Houston and the Carolinas hurricanes, they moved slowly, and so the rainfall totals were exceptionally large. And this is attributable—the slowing of the speed, in general, can be related to the global warming.

AMY GOODMAN: Emily Johnston, you co-founded 350.org in Seattle, Washington. As we wrap up, your thoughts on what your plans are, now that you are acquitted?

EMILY JOHNSTON: Well, in the immediate sense, you know, we are engaged in many climate campaigns in Seattle and in Washington state. There’s plenty of work to be done. I’m looking forward to getting back to it. A great majority of that work is legal, but we do engage in some civil disobedience actions. And, you know, we really—with this trial, we particularly wanted to do the necessity defense. This would have been sort of the dream trial in terms of our expert witnesses and our ability to present that defense. The fact that we couldn’t do that is pretty heartbreaking. And so I know a lot of people are still thinking about how can we try to have the—

AMY GOODMAN: We are going to have to end it—we’re going to have to end it there, but we’ll do Part 2 and post online—

EMILY JOHNSTON: Sure.

AMY GOODMAN: —at democracynow.org. Annette Klapstein and Emily Johnston, Kelsey Skaggs and Dr. James Hansen, thanks so much.