PAUL:
Welcome to Brainwaves, a podcast about big ideas produced at the 暗网禁区.
This week: The arctic is melting.
We鈥檒l look at how much ice we鈥檙e losing, why we should care and what we can do about it.
To dig into this, we鈥檙e going to start with someone who鈥檚 watched the decline in arctic ice firsthand.
Walt Meier is the senior research scientist at the National Snow and Ice Data Center, which is affiliated with CU Boulder.
The center just released the numbers on the low point of sea ice for the year.
And as Meier told Brainwaves鈥� Andrew Sorensen, those numbers paint a bleak picture.
ANDREW:
So, you've been tracking sea ice minimum for how many years now?
WALT:
We've been kind of tracking it day-by-day, and keeping track of the minimum since about 2005, is when we first started really keeping track every year.
础狈顿搁贰奥:听
And what is the minimum? What does that mean?
奥础尝罢:听
So the minimum鈥檚 where the ice gets to at the end of the summer melt season. The ice grows during the winter, and then it melts back during the summer. And it melts until the sun goes down and temperatures cool down. And then it starts growing again.听
And so, the minimum is that inflection point where it's bottomed out, and we're heading into autumn and winter.听
ANDREW:
And this year, it was pretty darn low.听
WALT:
Yes, it was pretty darn low. It was the second lowest in our satellite record, which is now 41 years we have. And it tied with 2016 in 2007, but still a fair bit above our record minimum which was in 2012.
ANDREW:
And, kind of, put this in perspective for us historically. How much sea ice is there? How much is gone at this point?
WALT:
At the end of the summer every year, so, back in the late 1970s early 1980s when our satellite record began, we were looking at about 6.5 to seven million square kilometers of sea ice at the end of summer.
That's a little bit less than the lower 48 United States, take a state or two off, and that's about what we're looking at. Now, we're regularly below five million square kilometers pretty much every year for the last dozen years or so or more. And oftentimes close to four million square kilometers like we were this year.
4.1, five million square kilometers so roughly about 40% less than what we used to have back in the early 1980s.
ANDREW:
Is that alarming to you?
奥础尝罢:听
I think it's alarming. I think, you know, to have something change that quickly and that much is substantial. You know, it's, it's something that's changing within a generation, essentially.听
We're taking away almost half of the United States of sea ice cover. You're taking something that's white, essentially鈥攕ea ice鈥攁nd replacing it with a dark ocean. There's big implications, both within the Arctic and outside of the Arctic.
ANDREW:
Tell us a little bit more about that difference between dark ocean and white sea ice.
WALT:
Yeah, so the sea ice is reflective. So, it reflects the sun's energy, and during the summertime you have 24 hours of daylight, 24 hours of sunshine coming down to the surface. And most of that gets reflected by the ice cover, 60-70% depending on the condition of the ice.听
But when you lose the ice, the ocean absorbs almost all of it, absorbs over 90%. And all that absorbed energy from the sun heats the ocean.
So the ocean warms up and makes the Arctic a much warmer place than if you had ice there.听
ANDREW:
So, as you've been watching this, 40 percent lost, you say, is pretty alarming. Is there chance for that to turn around? Is that possible?
WALT:
So, the declining trend is due to warming temperatures. The Arctic is warming twice as fast as the rest of the globe. And some of that is, because of this, what we call a 鈥渇eedback,鈥� where the ocean is absorbing more energy and warming things up even more. But ultimately, warmer temperatures, less ice. It's pretty obvious. When you warm things up, things are going to melt. But the thing with the sea ice cover is it's changed rapidly, because it's pretty thin. It's on the order of maybe 10 feet thick, less now than it used to be. But it doesn't take a lot of energy to melt it. But that means it doesn't take a huge change to go back.
And so, if temperatures were to go down again, we would bring the ice back fairly quickly, within,, you know, maybe a decade or two. So, it's, it's definitely not a lost cause. But as long as temperatures are high and increasing, we're going to continue to lose ice.
ANDREW:
How much would temperatures have to go back to replace that sea ice?
WALT:
That's a good question. I think it's hard to say. I mean, I think it responds pretty, pretty straightforward, pretty linearly with temperatures from what we've seen. So, if we go back to temperatures that we used to have, you know like the one- or two-degrees lower temperatures, it would probably go back to what we were at back in the 1970s.听
ANDREW:
And then, just from what you're seeing, you're obviously deeply involved in climate science, I think one of the questions out there in people's minds: The numbers come out about people saying, 鈥淲ell, there's not consensus about climate change within the scientific community.鈥澨�
As someone involved in climate science, do you see consensus or not?听
WALT:
There's definitely consensus. That's not to say there's not some uncertainties, there's not some quibbles about things, but the big picture: Is climate changing? Is the globe warming? And are humans contributing significantly to it? That's pretty much universal amongst legitimate climate scientists.
So, there's really very little doubt of that. And sea ice is one of the iconic indicators of that. It's hard to see or to feel a degree or two warming here in Colorado or other places, you know. And so, I can kind of understand the skepticism here, like, 鈥淚 don't really see climate change.鈥� But when you look at the Arctic Ocean, and you see almost half of the Arctic Ocean going from ice covered to ocean, that's a big change. And it's really hard to deny that.
ANDREW:
Okay, anything else want to add?
奥础尝罢:听
So, I think the only other thing, in terms of our long-term record, we have 41 years. That's our most recent satellite record. We have other data that goes back farther and puts this into a longer term context. And we're still very low compared to anything in our records going back hundreds, probably even thousands of, years. And I think the telling thing is that people might look at 2012鈥攖hat was the record low鈥攚e haven't reached that. So, you know, hey are we really continuing to go downward? But you look at the trend, and it's downward. And one of the things that I think is quite striking about our record is that out of the 41 year record, the 13 lowest extents that we've had are the last 13 years: 2007 to 2019. That's not just random chance. That's just not whether there's something more going on there. And I think that's a that's a big indicator right there.
ANDREW:
Alright, thank you so much听
WALT:
All right, thank you.
PAUL:
We鈥檙e hearing more about climate reports in the news, but we had to ask: a millimeter of ice melt here, a foot of sea level rise there, does it make a difference to you?
How much are you paying attention to all of the climate reports coming out?
Brainwaves鈥� Cole Hemstreet asked around.
COLE:
The new United Nations Climate Report was released last week and unsurprisingly, things aren鈥檛 looking great.听
The report primarily focuses on substantial ocean level rise caused by melting icebergs in Greenland and Antarctica.
The report projects a 3.6 foot ocean rise across the globe by 2020.
A 2013 report pegged that number at 3 feet, meaning the acceleration seems to be faster than we can predict.听
But here鈥檚 a question鈥� are we paying attention? Or is this all just noise?
PERSON 1:
I should have. I work for NOAA, and I have no idea what was in it. I鈥檓 assuming it鈥檚 bad and we鈥檙e all going to die.
PERSON 2:
No.
PERSON 3:
No. Haha.
PERSON 4:
No.
PERSON 5:
No.
PERSON 6:
I did not.
PERSON 7:
I did not.
PERSON 8:
Besides what I saw on television, no.
PERSON 9:
I鈥檓 a terrible citizen I know.
PAUL:
Whether we pay attention or not gets us to another question.
Why should we care?
Brainwaves鈥� Dirk Martin talked about that with Twila Moon, another ice researcher at the NSIDC.
DIRK:
If I live in a place like Texas, why should I care about sea ice?
罢奥滨尝础:听
Yeah, that's one of the difficulties that we often have thinking about changes that are happening in places far away in the poles.听
But in fact, the changes that are happening in the poles, for example, the Arctic, do impact the climate and weather events that we feel far away in places like Texas.听
So, for example, in the Arctic, where we've seen dramatic reductions in sea ice, both in how much area of ocean it covers, as well as how thick that sea ice is. And so, as we're losing that sea ice in the Arctic, you can imagine that ice, and sometimes with snow on it, is almost white. And so, it's highly reflective and solar radiation is coming in from the sun, and reflecting off of that bright surface, back out into space. And in that way, sea ice helps the earth not take up as much energy or heat from the sun.听
But when we lose sea ice, we're replacing that with open ocean, and if you've ever seen a picture of the Earth from space, you can recall that oceans are deep, deep blue, almost black looking from space. And what happens then, is that, that very dark ocean then can absorb a lot of energy, or radiation, or heat from the sun. So, we switch from a surface that reflects about 90% of the sun's radiation to one that's absorbing about 90% of it. And that heats up the ocean, and that heat in the ocean moves around the ocean, and can also be released back into the atmosphere. And that causes additional warming around the globe.听
So, temperatures that we see, for example, at your home in Texas, are actually going to be higher, because we are gaining heat in, in the Arctic because of sea ice loss.
顿滨搁碍:听
Well, what are some of the real-world impacts people who live in the US will see from sea ice melt? You just explained a couple things that might happen in terms of a warmer atmosphere. But across the US, what can we expect?
TWILA:
The types of connections that we have to changing sea ice primarily do connect with how that loss of sea ice is influencing our climate and our larger air temperatures.听
And it may be that鈥攖his is an area of ongoing research鈥攂ut it may be that losses in sea ice are also changing some of the differences in temperature between the mid- and low-latitudes, the equator, and the US and the poles and changing how our jet stream moves, perhaps changing the character of storms and different weather patterns as well.听
DIRK:
Well, it's not only sea ice that鈥檚 melting, but the land ice, our glaciers, are also melting. What impact is that going to have on, on us?
TWILA:
The loss of land ice is one of the biggest contributors to sea-level rise around the world. And that's something that we are already experiencing.听
For example, in the US, we've already seen sea levels that have risen six to 10 inches or more in different places over the last 25 years. And that's why we hear about increased flooding for that person in coastal Texas, and Houston, or in Florida, or we hear about coastal erosion happening in California, or places where people's drinking water is threatened, because we have salt water that can suddenly get to places that were previously freshwater.听
So, we have health concerns from rising sea levels.
DIRK: Do you see a day where we do not have land ice in the lower 48?
TWILA:
Unfortunately, I do think it is possible to imagine a time when we no longer have land ice in the lower 48 areas, like Glacier National Park, and the glaciers that we see in the Pacific Northwest, as well as glaciers further south in the Rockies. These are already experiencing substantial amounts of ice loss, and people can go in and see that loss by visiting Glacier National Park, or Olympic National Park or other places with glaciers that have well documented how much ice loss we've already seen.听
And for, unfortunately, for many of these glaciers, we do expect to lose them in the next few decades. And that's going to have impacts on ecosystems as we lose that cold freshwater, it's going to have impacts on people who use glacier water to help with drinking water, hydropower or agriculture.听
But for some glaciers, there's still a big difference in how much ice we'll lose, and how quickly we鈥檒l lose (it), based on human actions.听
So, people should certainly go and visit these and experience those changes in ice themselves. I think that's very powerful, and in fact, we can have a very substantial influence on how much land ice sticks around and helps provide those important services.听
DIRK:
Twila Moon, thank you for talking to us on Brainwaves.
TWILA:
Thank you for having me. It's been a pleasure.
Join us next week, when we plan to take on why we get a kick out of being afraid.
Thanks for listening to this episode of Brainwaves.
I鈥檓 Paul Beique.
This episode was produced by Dirk Martin, Cole Hemstreet and myself.
Andrew Sorensen is our executive producer.
Sam Linnerooth is our digital producer.
And Cole created our introduction.
See you next time on Brainwaves.
听