Climate Change

A quick note of correction: In Tom Armstrong's second answer, he says "16 gigatons." That number should actually be 1,000 gigatons. He also says "3 gigatons"—that should be 300 gigatons. Sorry for the errors, and enjoy the podcast.

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Pat Jellison [voice]



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Music credit:



"Naughty Hula Eyes," Andy Iona

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Scott



So, welcome and thanks for tuning into the second episode of the USGS CoreCast. I’m Scott Horvath. If you've already listened to Steve Sobieszczyk our previous podcast (we call Steve "Sobie" for short, for obvious reasons) then you know that we have a series of podcasts called the CoreCast Science Focus. Well, this time around I'm going to be talking with Tom Armstrong, who is the Senior Advisor to the Director on Climate Change in our next spot in this series, appropriately called CoreCast Science Focus: Climate Change. So, without further ado, let's talk about some climate. Tom thank you for joining me today.

Tom



Thanks a lot, Scott.

Scott



I just wanted to go over a few questions with you regarding climate change and get some really down to earth answers from you. So we’re going to start off. As you well know, over the past few years there have been major weather-related events like Hurricane Katrina and Rita, heat waves, tornadoes in areas of the country that don’t typically experience tornado activity, and even wildfires which of course is a major topic right now. Many people, including respected scientists and media, attribute this rise in extreme weather events to climate change. So, is climate change to blame for these types of events?

Tom



That’s a good question Scott, and the answer is “sometimes.” There is a difference between weather and climate. Climate is the long-term look at weather phenomena or changes in how things occur that impact weather. But specific events such as the intensity of strong storms, including hurricanes, the development of tornado-prone conditions, have been attributed, in part, changing climate. There’s been a lot of work looking at changes in sea surface temperatures and how that may influence and enhance the generation of strong storms. Not the frequency of them, but the intensity of them. So there are connections between weather-related phenomena and climate change. But not all weather phenomena can be blamed on climate change.

Scott



Right. Okay. Many people, of course, have probably seen the movie “the Inconvenient Truth” with Al Gore. Which talks about the idea of “quote/unquote” Global Warming and how it’s being caused or how it’s being caused in part by the increase of carbon into the atmosphere. Which disrupts the normal carbon cycle through the use of factories or cars and the like. But, really, how significant is the carbon cycle to climate change? For example, does climate change influence the carbon cycle or does the carbon cycle influence climate change? And for those of us who don’t know, could you briefly explain what the carbon cycle is, in Layman’s terms?

Tom



The carbon cycle is basically just a look at how carbon moves between the atmosphere, the oceans, and the earth…the terrestrial part of the earth. There’s a budget of carbon on our planet within our whole earth system, including the atmosphere that purportedly doesn’t change. But where it actually resides in the air, the water, or the earth changes very quickly and very frequently across the planet. So that’s the carbon budget, it’s sort of like the budget of whatever money you have locked up in a bank. It might move from one teller to another, and that’s really the tricky part is, where is the carbon at any given time.

The answer to your question, though, about which one impacts the other; they impact each other. Carbon cycle impacts climate change and climate change impacts carbon, and let me give you an example of what I mean. [Host (Scott): Sure] There are about sixteen gigatons, which is a boatload [Laughter] of carbon locked up in the arctic permafrost worldwide, the frozen ground of the arctic. Just to give you a prospective of how much sixteen gigatons is…in all of human history, from the start of man to the present, we have only emitted, as people, about three gigatons of carbon. So this is a lot more than all the carbon that’s come from cars, boats, trains, planes, whatever, since man’s been on the planet.

Right now, the entire realm of arctic permafrost, where that carbon…that sixteen gigatons is locked up is on the verge of melting due to global warming. If the permafrost does melt or thaw, and that sixteen gigatons of carbon is released…a lot of that will go to the atmosphere from the Earth, into the atmospheric part of the budget and that will promote greenhouse gas concentrations and lead to warmer temperatures. So, in that case, the carbon cycle affects climate. But if temperatures rise, there will be more warming and more of the permafrost will melt. So, in that case, the carbon cycle is impacted by climate. So it’s what we call a positive feedback loop. They’re both interrelated. It’s a chicken and the egg kind of thing.

Scott



Right. So let's talk a little bit about the effects that climate change is having. As we talk about climage change, we talk about the carbon cycle, how it's affecting us and of course our planet’s future, for that matter, what kinds of impacts to the population, to natural resources, or even infrastructure might occur within the next several years as a consequence of climate change? What do these impacts mean for the everyday, Average Joe, like myself who might not be aware of what's actually taking place. What does that mean to us?

Tom



That’s a really great question and I liked the way you phrased it, and that was “impacts.” And impacts can be both positive and negative. In the past we have seen cases of global warming or natural climate variability in change in which temperatures have risen. Back about a thousand years ago temperature rise led to the movement of the Vikings from Scandinavia to Greenland because that area was available for agricultural purposes and for farming. It was a positive opportunity. It was a case in which climate change led to man’s ability to adapt to other parts of the landscape.

So in some cases it can be a very positive thing. It depends on where you are whether your perspective is it’s a positive thing or a negative thing. But the kinds of impacts that might be felt are we may see and increase in sea level rise. Areas of the coast that are currently beach front property may be part of marine environment over the course of the next hundred to thousand years. We will see changes in precipitation patterns. Areas that are flood-prone today may be even more flood-prone tomorrow, or may dry up and be less flood-prone tomorrow depending on where they are. So what’s good for one group of people on one part of the landscape may be bad for another group of people.

But impacts to our water availability, sea level rise, recreational activities, glacial retreat, there’s a whole host of things that people will see as every day impacts that we’re already becoming aware of. Changes to our water supplies, especially in drought-prone areas and in population areas where there is a huge demand for water. Those systems are already being stressed, so we are already seeing impacts of climate change today.

Scott



OK, now regarding those impacts that you just spoke about, are we going to be able to see those happen overnight? Can they happen over night? Or will they happen over a period of time?

Tom



That’s another really good question and right now the changes have been subtle and slow. Slow enough that we’ve been able to either mitigate them, or that is remediate the problem or adapt to them. One of the things that really keeps climate change scientists awake at night is the possibility of what we call “abrupt climate change events.” And the past geologic record has shown that climate can change very quickly.

For example, there have been many periods in the geologic record that we can examine, and the USGS has examined where climate has changed over twenty degrees Fahrenheit in the course of one, two or three decades. Those kinds of dramatic mean annual temperature changes, where you’re seeing twenty degrees Fahrenheit change in annual global temperature over the course of, say, ten or twenty or thirty years is so quick that ecosystems and people will have a very hard time adapting to those changes.

Those abrupt change events are not necessarily over night, but in the terms of a geologic record of climate change, that’s almost instantaneous. And how systems and people will adapt to that is of great concern us and decision makers.

Scott



Great. So…okay, we’ve touched ona little bit of how rapid are the changes and I sort of wanted to talk just briefly about the glaciers melting and, for instance, ice shelves receding. We're constantly hearing about the media, or scientists talking about sea level rise related to melting of glaciers and ice shelves receding. Exactly how much additional sea level rise is going to result or will possibly result from rapidly melting glaciers, for example?

Tom



That’s…again, another question that scientists are very concerned about today. The recent intergovernmental panel on climate change report that just came out of Paris in February dealt with the growing concern of sea level rise across the globe. Most of the scientific, peer-reviewed literature that was used by the IPCC for the most recent fourth assessment deals with the issue of continued global warming and the related expansion of the current volume of sea water due to its warming. As water warms, it just expands.

As it expands, sea level will rise. The piece you just touched upon the accelerated melting of terrestrial, earthbound ice will add to the water budget. How much it will add is of great concern and a great question in science right now. Some of the estimates that have come out are that, for example, if all the ice on Greenland were to melt over the next ten or fifty years, or however long it might be…that contribution of water to the total ocean volume would lead to a sea level rise of maybe six meters. And if won’t occur gradually, it’ll occur in abrupt, sort of steps.

Right now, a lot of the science that’s going on across the world on Iceland, Greenland, ice…terrestrial ice, mountain glaciers, and the west Antarctic ice-sheet indicate there is reason to believe that the rate of melting these ice sheets in many places is accelerating. And if this continues, the IPCC assessment of looking at maybe a millimeter per year of sea level rise may be a gross underestimate. And what we might be looking at is over the next one hundred years we may see a change in sea level at a meter or more, which leads to a lot of concern globally, as well.

Scott

Great. So I did want to touch on one...one more question, specifically regarding the USGS. Today, the USGS has played a major role in climate change science in making sure that the accurate and peer-reviewed science is, of course, disseminated to the public as quickly as possible. Could you tell me some of the major contributions that the USGS has done and what future contributions we might be able to make to climate change science? In addition, this sort of goes with that major role part, but could you explain what unique niche the USGS fills within the area of climate change science?

Tom



Sure. There are many, many significant contributions our scientists have made at USGS in the past and currently to the field of climate change and its effects. Just to list a few of them to you; understanding the causes and mechanisms in the geologic record of abrupt climate change, when they’ve occurred, why they’ve occurred and what the impacts have been. So by looking at the past we better understand what the future will be.

Studies of our scientists out looking at climate change over the term of the last fifty years and its impacts on water availability, drought and flooding. The impacts of climate change on biodiversity, ecosystem health, proliferation of evasive species, emerging diseases, impacts on threatened and endangered species.

USGS is a leader for many of the natural resource agencies at both the state and federal level, for managing these critical and threatened and endangered species. There’s a host of many other things, famine early warning system and its relationship to climate change. We’ve been a leader in that field as well. One of the major paradigm shifts, Scott, a big, sort of philosophical change is I think we’re getting away from arguing about is climate change real or not? Certainly the consensus amongst most scientists is that climate change is real, we need to start deal with its effects.

USGS with its multidisciplinary capabilities in geology, biology, hydrology and geography is poised to lead the way in understanding the ground-truthing of climate change science and the impacts of climate change on people, land, and ecosystems. That’s really where our niche is…the ability to work at any scale both from the plot level to satellite-based remote sensing. And to work in any part of the globe, frankly…not just the United States, on both private and public lands in a multidisciplinary fashion where we integrate everything to look at the holistic earth system.

We have a niche in not really addressing is climate change real, but moving beyond that now to what are going to be and are the impacts of climate change on people, land and ecosystems. We have a leadership role to play in that.

Scott



Excellent. So it’s good to hear that the USGS is certainly moving ahead and taking part and continuing this major role within climate change science. So Tom, with that, I appreciate your time, and thanks for doing this, and have a good day.

Tom



Thank you, you too.

Scott



So that does it for this episode of the CoreCast. Hopefully everyone listening has learned a little bit more about climate change and some of the science behind it. If you do want to learn more about the details of climate change science or what the USGS is doing, along with a host of other resources as well, you can visit the USGS Climate Change Science Web site, got that right, at geochange (that's g e o change) dot er dot usgs dot gov.

Thank you for listening to a USGS CoreCast. For a complete transcript of this podcast and our first podcast, that hopefully you listened to on Hurrican Research...plug plug...please visit www dot usgs dot gov and you can click the "Podcasts" tab at the top of the page.

CoreCast is a product of the U.S. Geological Survey, Department of the Interior. Until next time, I'm Scott Horvath saying, "Keep it cool."

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Music credit:

"Nobody's Dirty Business" by Mississippi John Hurt

Mentioned in this segment:

• USGS Climate Change Science Web site
• USGS Web site