IRA FLATOW: This is Science Friday. I am Ira Flatow. A bit later in the hour, we’re going to talk about the worldwide increase in C-sections. And if you have a story you’d like to share with us about your C-section or your partner’s C-section– why you had it, how did it go, what was it like– please share it with us. Give us a call– 844-724-8255. Or you can tweet us, @scifri. Phone, 844-724-8255, or tweet @scifri.

But first, last week’s report from the Intergovernmental Panel on Climate Change gave us a sobering look at what a world worn by 2 degrees Celsius might look like. Then on the heels of that report, ExxonMobil announced that it was throwing financial support behind a US carbon tax. It’s a big step for one of the world’s largest oil companies, which last year was sued by its own employees for misleading statements about the environmental and financial impact of fossil fuels and has a history of denying the climate science settled.

Here with the story, as well as other short subjects in science, is Umair Irfan. He’s a staff writer for Vox. Umair, welcome back to Science Friday.

UMAIR IRFAN: Thanks for having me again.

IRA FLATOW: So Exxon says it’s going to back US carbon tax. And on the surface, that sounds like a good thing. But what exactly are they proposing?

UMAIR IRFAN: They’re proposing to back a lobbying effort launched by conservative former secretaries of state George Schultz and James Baker. This is a group called the Climate Leadership Council. And it proposes starting with a $40 per ton price on carbon dioxide emissions, and that price would rise over time. Then they would use that money to go back to people like you and me, essentially in the form of a dividend or a rebate, and the estimate is it would start at about $2,000 a year for a family of four.

There is a catch, though, and Exxon wants rollbacks of other environmental regulations. And one big catch is that they want immunity from climate change related lawsuits that want damages for these companies.

IRA FLATOW: That’s the same deal that the gun producers have.

UMAIR IRFAN: Yeah, pretty much. It’s kind of analogous to what they got. And it’s what other industries have also tried to get.

IRA FLATOW: Hmm. Exxon has a complicated relationship with climate change. It’s been ahead of the industry in acknowledging it’s a problem. They’ve had researchers who helped author the IPCC report. And yet, they are also being sued for misleading people about the impact of fossil fuels years ago. And in 2000, they took out ads in newspapers saying that the science was not settled. I mean, should we be taking this seriously? Or is it just another “make us look good” sort of thing?

UMAIR IRFAN: That’s always the question, isn’t it? I mean, the thing to remember about Exxon is that they are an investor-owned company. So they do have to answer to their shareholders. And they’ve been getting a lot of pressure in shareholder meetings to better address climate change. Also, climate change poses a business risk for them in terms of their facilities. And if they aren’t out ahead on this, they might get slapped with a carbon policy that they don’t like that doesn’t actually work in their favor.

And another way a carbon tax might actually benefit them is that it would target the dirtier fuels– first, things like coal, which would clear some space for one of Exxon’s other products, natural gas. And of course, the catch is the things they wanted exchanged for getting the other environmental regulations rolled back and the immunity from lawsuits– I mean, those are all things that benefit the company. So this could be viewed as an act of self-interest overall.

IRA FLATOW: Yeah. We’re going to have to look deeper into this in the weeks to come. Let’s move on to, speaking of a warming planet, there are a couple of new studies this week that show massive losses of wildlife that has scientists worried. Tell us about that.

UMAIR IRFAN: Yeah. There are a couple of different studies that kind of have a grim outlook for what humanity is doing to nature. One of them looked at arthropods in Puerto Rico, which includes insects, centipedes, and spiders, creatures like that. They’re critical to ecosystems because they perform functions like pollinating plants. And they’re also crucial foods. So they’re at the bottom of the food pyramid, so to speak.

But the forest ecosystems have been changing faster than the rest of the planet. You know the, planet has warmed 1 degree since pre-industrial times. Forests have warmed, on average, by 2 degrees. And that’s had a pretty consequential effect. And so in the first study, the researchers, they did sort of a population census of arthropods in Puerto Rico. And with one method using nets, they found an eight-fold decline. And then using their sticky traps, which is another method of counting insects, they found an upward of 60-fold decrease in these invertebrates.

Now, this doesn’t spell extinction, per se. But it does show that there has been a drastic, drastic decline. And scientists have called this one of the most disturbing articles they’ve ever read.

The other big study that also came out looked at mammals, specifically mammals that have gone extinct due to human activity. Since humans have started walking the earth, we’ve seen more than 300 mammal species disappear. But what’s unique about this study is they tried to quantify how unique these animals were– not just the numbers, but how irreplaceable they are.

So as mammals share a common ancestor, they branched out on the tree of life. And it turns out humans have been severing entire limbs off of the tree. And in aggregate, we have cost nature about 2.5 billion years worth of phylogenetic diversity, as they call it.

IRA FLATOW: Can you give me an example of one of those branches that was severed?

UMAIR IRFAN: Sure. Ed Yong, writing in the Atlantic, he gave the example of the pygmy sloth, which is a threatened species. It branched off from its common ancestor about 9,000 years ago, which makes it a very young species, and so a kind of a small twig on the tree. But then there are animals like the aardvark, which is the last survivor in its group. And it branched off 75 million years ago. So that means that if we were to lose those animals, that’s a thing that would take millions of years to regenerate in terms of diversity.

IRA FLATOW: Yeah. I get it. Let’s move on. There’s an ongoing outbreak of Ebola in the Democratic Republic of the Congo. We reported on that back in August when it first began. So give us an update on what the status is now.

UMAIR IRFAN: Well, the outbreak is still outgoing. There have been 223 cases and 144 deaths, according to the World Health Organization’s latest report. They met this week to determine whether or not this counts as a global health emergency. This is a declaration that would mobilize more international resources. But it also has sort of tradeoffs, because countries will respond to that by imposing travel restrictions and quarantines, which can make it harder to get supplies in.

So health officials have to be kind of careful about making these kinds of declarations. And they declined to make it a global health emergency. They made it a regional emergency. And what’s scary, and just kind of unnerving, about this outbreak is that it’s occurring in an active war zone.

IRA FLATOW: Oh. That makes it tougher to get in there and do something about it.

UMAIR IRFAN: Yeah, that’s right.

IRA FLATOW: Is there any reason for hope then?

UMAIR IRFAN: Yeah. This is actually one of the first live trials of a vaccine. We now have an effective Ebola vaccine. But of course, the ongoing conflict in the North Kivu region of the Democratic Republic of the Congo makes it harder to get health workers in. Health workers have been attacked in the past. And then they have had to be escorted by armed personnel, which in turn breeds distrust among the locals.

And there is a limitation to how many resources that are going in. And so rather than using a blanket vaccination strategy, they’re doing what’s called ring vaccination, where they track infected individuals and then try to vaccinate everybody around them– the caretakers and family members– to help sort of contain the virus in a more efficient way.

IRA FLATOW: Great stuff, Umair. Thanks for taking time to be with us today.

UMAIR IRFAN: Likewise. Thanks for having me.

IRA FLATOW: Umair Irfan is a staff reporter for Vox.

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