The Daily Signal - Climate Series Part 1: History of Climate Change

Episode Date: January 3, 2024

Climate change has strayed from being a scientific conversation to a hot-button political debate. But what are the facts surrounding climate change? Is climate change real? And if it is, what is causing the climate to change? Do we need to live in fear of climate change? In a three-part "Daily Signal Podcast" series, experts in the fields of climate and meteorology join the show to explain the history of climate change, its root causes and the appropriate response to it.  Here in episode one, David Legates—a visiting fellow with the Science Advisory Committee in the Center for Energy, Climate and Environment at The Heritage Foundation and a former director of the Center for Climatic Research at the University of Delaware, explains the history of climate change. (The Daily Signal is the news outlet of The Heritage Foundation.) According to Legates, “the climate is changing because it always has changed, and it always will change.”  “We've gone through periods of lots of tornadoes, for example, and then a period where we have almost none,” Legates says. “We've gone through periods where we have lots of hurricanes. We have floods, we have droughts. We go through periodic cycles. So, the climate is sort of the backdrop on which weather plays its randomness, if you want. So, climate does change, always has changed, and as far as I'm concerned, always will change.” Legates goes on to explain what is known about climate change through the ages and the similarities between climate change patterns today and those seen in the past.  Enjoy the show! Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit megaphone.fm/adchoices

This is the Daily Signal podcast for Wednesday, January 3rd. I'm Virginia Allen. Is climate change real? And if it is, what is causing the climate to change? Do we need to live in fear of climate change? And is it driven by a political agenda? Starting today, we are diving into these questions over the course of a three-part podcast series, centered around the issue of climate change. These are honest conversations. with some of the leading minds and experts on the issue. And we're kicking off this three-part series today with expert David Legates. He explains what we know about the history of climate change and just how much the climate has changed in recent years.

Stay tuned for our conversation after this. So what is going on with Ukraine? What is this deal with the border? How do you feel? about school choice. These are the questions that come up to conservatives sitting at parties, at dinner, at family reunions. What do you say when these questions come up? I'm Mark Geine, the host of the podcast for you. Heritage Explains brought to you by all of your friends here at the Heritage Foundation. Through the creative use of stories, the knowledge of our super

passionate experts, we bring you the most important policy issues of the day and break them down in a way that is understandable. So check out Heritage Explains wherever you get your podcasts. It is my pleasure today as we are kicking off our Climate Change Daily Signal podcast series to welcome to the show David Legates. David serves as a visiting fellow for the Science Advisory Committee in the Center for Energy, Climate and Environment here at the Heritage Foundation and has an impressive resume of expertise around this area of climate and discussing climate change. So, David, thank you for being with us today to have this important conversation. Thank you. It's a pleasure to be here.

Well, I want to begin by asking you to share a little bit of that resume and your background and how you got into the field of climate studies. Well, actually, I'm now retired. I spent about 20 years back here at the University of Delaware. I got my original degrees here. I was faculty for, well, since 1999, before that, I was on the faculty at the University of Oklahoma and Louisiana State University. Back when I got out, or got out of high school, which was a long time ago, I wanted to be a weather

forecaster. And to make a long story short, I went to the University of Delaware, and I talked to somebody there, John Mather, and he said, you know, the future is going to be climate change. and it's not going to be weather forecasting. So you really need to think about changing your focus. And I wasn't sure whether it was giving me a line or not. So I went over to the University of Maryland where it also been accepted. And I literally walked in off the street and they set me up with a famous climatologist.

And he essentially said the same thing. And I said, I've heard this at Delaware and he said, climate is where you should be. Delaware is where you should be. You should not be here at the University of Maryland. And that's where I am today. So I got out of weather forecasting very early on, even before I started, and was interested in climate change while it was still global cooling. Wow. So you've been in the weeds for a long time.

So then I think it's important as we start this conversation, start this three-part series talking about climate change. To start with the very big question and just sort of lay the foundation, is the climate changing? Yes or no? Let's just go ahead and get that out of the way. Unequivocably, the climate is changing because it always has changed and it always will change. The problem is we got into a definition where we said, climate is nothing more than average weather. Weather is where all the fun is, weather is where all the changing is. Climate is just simply an actuarial science.

Means, standard deviations, maximum, minimum, those kinds of fun things. But they're not supposed to change somehow. And when they do, uh-oh, this is a disaster in the making, we've got to. got to stop it from changing. But climate has always changed. We've gone through periods of lots of tornadoes, for example, and then a period where we have almost none. We've gone through periods where we have lots of hurricanes. We have floods. We have droughts. We go through periodic cycles. So the climate is sort of the backdrop on which weather plays its randomness, if you want. So climate does change, always has changed. And as far as I'm concerned, always will change.

What kind of historical records do we have in relation to climate change? What do we know about what the climate was doing a thousand years ago? What do we have as far as the history of climate change on this planet? Well, back like 1,000, 2,000 years ago, we have to use proxy records. We look at reports of people talking about things such as the flooding of the Nile River. We look at things like when certain trees bud. There's some excellent records, long-term records. For example, in China.

There's excellent records in places in Europe. Problem is, they're few and far between. We can also use such things as tree ring analysis. We can make assumptions based upon isotopes of oxygen, for example, as to whether the temperature was warm, cold, lots of rainfall, lots of ice, things like that. But really, when we start to measure temperature, we started in the mid-1800s,

And of course, the problem is that record, while it got more populated to the 1980s, it's actually become less populated. The problem is we have very few rain gauges on the planet. Effectively, the argument somebody said is that if you counted up all the rain gauges in the United States, and the United States is where we have the most, the densest network that exists, if we took them all together, took all that area, it would fit inside the diamond of a baseball field, from home plate to first, second, third base. That area is all we're measuring in the United States. And the United States has a very dense network. The problem is our stations are located where people live. They're primarily in middle latitudes at low elevation. There's very few

stations, obviously over the ocean, in high latitudes, down in the tropics, and very few at high altitudes. So we don't have a good coverage of station data. We try to make the best we can. Part of the problem is stations come, stations go, stations move, and in particular we change the way in which we've measured temperature. We're not using the same types of thermometers today, for example, than we were in 1900. So there's all these fundamental problems in trying to take a bunch of thermometer data, put it together, and come up with this globally averaged air temperature that we all want to track and see how it goes and look at really small changes in air temperature and, you know, We're about to hear this has been the warmest year on record.

But can we really say that? I don't think we can. And I think that's the problem is that our measuring network just isn't up to snuff with respect to what we would like it to be. So there's a lot of moving parts is what it sounds like. And it's hard to say with certainty because technology obviously has changed. And there's all those factors that you just mentioned. So considering that factors have changed so much and, you know, it's hard to say.

with certainty, what was happening 200 years ago based on recording in comparison to today. What do we know about cycles of warming when you have much of, you know, the scientific community talking about how we're in the cycle of warming right now and, you know, folks talking about the climate getting hotter and pointing things, pointing to things like emissions contributing to that? What do we know about warming cycles in the past and how confidently are we able to say, or are we at all that we have seen a similar cycle to what we're seeing right now? Well, we can say that over the last thousand years that there was a warmer period back about 1,200,400 A.D., which was known as the medieval warm period.

Things were generally warmer during that period. Vikings settled Greenland, for example. And then we dropped into a cold period known as a little ice age. It's a misnomer. It wasn't an ice age at all. A little cold period, however, doesn't quite have the same cachet. But that lasted until about 1850. So over the last thousand years, we've seen a warm period, followed by a cold period.

And since then, we have warmed. So unfortunately, our thermometers start recording right at the end of the little cold period and have been recording since then. We've been warming since then. We've warmed from about 1850 to 1940, then the temperature dropped to about 1980, which is when global cooling was all the rage. And then from 1980, it turned around and started up again,

and now we've seen warming largely since then. There have been periods of what we've referred to as the hiatus, where temperature appears not to have warmed for 10, 12, 14 years. at a time, but nevertheless, generally we're in a warmer period now, and that's a good thing. Warmer periods generally see civilizations do better. Cold kills more people. Warm is more easy to deal with. It creates longer growing seasons. It creates lots of food. And civilizations generally have grown more when the temperature has been warmer than when the temperature has been colder.

Okay. Fascinating. Are we seeing that there is a shift happening more? quickly that we're aware of between the cycles of cooling and warming, has the process been sped up at all? Or is it pretty even from what we can tell from historical records of, you know, there's about X number of years between or X number of years that these cycles last? Well, see, the question is whether we're talking about global warming or we're talking about local warming. Okay. The issue with local warming is that where our thermometers are located, have a tendency to be in urban areas or on urban fringes. And we have something in climatology that we've long known about called the urban heat

island effect, that cities tend to be warmer than the surrounding countryside because of the retained heat of the city, which keeps nighttime temperatures warmer than the surrounding countryside. I mean, if you're in D.C., for example, and you're watching the television at night, and you've got a night where there is very little weather going on, it's sort of a nice calm night, you'll see that downtown Washington is going to be much warmer than, say, out in the hinterlands outside of the Beltway. So generally the problem has been, for example, I don't use Washington as example, when we started to put in our weather stations at the airports in the 1940s.

After World War II, we recognize that we've got these flying machines. They need to have weather forecasts. Why put these things, the weather station downtown? why not move it out to the airports? And the airports were built in the countryside. Dulles Airport, for example, if you look at the early pictures, it was in the middle of nowhere. And now you know very well it's not. It's surrounded by urban sprawl.

So what we've seen at the temperature measurement at Dulles is the temperature has gone up. Is that because the temperature rose globally or is it because of the urban heat island effect locally on that thermometer? and multiply that not just in Washington, but look at New York, Philadelphia, I mean, you can go out, every big city's got this problem with the urban growth over time. So the question we have to ask is, as our temperatures are rising, what extent is it rising because of a background signal in climate? And what extent are we simply seeing a local fluctuation due to the fact that our thermometer is now in a different setting? It used to be in rural areas. Now it's in urban areas and it's warmed not because the background temperature has changed,

but because the local temperatures changed. And that adds an even more complexity on trying to figure out what we really mean by a global temperature. And are scientists and climatologists taking that into consideration always when they're, for example, for those that are concerned about climate change and are speaking about it and the concerns and are even advocating for things like, you know, caps on emissions, CO2 emissions and all of that. Are they taking those factors into consideration when they issue their warnings? You would hope they would. What we're finding is generally some of the adjustments that they make to the data set,

and I'm not suggesting that adjustments are bad, but the adjustments that are making for the urban heat island are actually leading to warming in the more recent portion of the era. And that's where you would expect actually us to be decreasing the temperature, not increasing the temperature. The other problem we have with NOAA is that NOAA has what are a number of called ghost stations. Without getting too much into the weeds, when you try to interpolate a large-scale estimate,

you need to have stations there all the time. Well, Noah's network over time slowly is decreasing in number. So what happens when a station disappear? Well, for example, there's a station about four miles from me. It stopped measuring in 1985. However, I can go to the NOAA weather station. NOAA is the National Oceanic and Atmospheric Administration as part of Department of Commerce. They run a national network of weather stations.

I can go to where that station used to be. There's nothing there right now, but I can go to the NOAA website, and I can actually get a temperature observation for the past month every day. Well, how's that happen? There's no station there. Well, it's because they make it up. They estimate it from surrounding stations. And that becomes a problem because they're treating as data estimates. And while that works for your interpolation algorithm,

a lot of cases where stations that were measuring lower temperatures, say at the top of the mountain, if that goes away, that estimate gets incorporated into a lot of lower-lying stations, lower elevation stations. The temperature of that estimate immediately jumps up. and all of a sudden a large area now becomes warmer than it would have been. It's not true. It's designed, by the way in which we've tried to come up with what we mean by large-scale mean temperature.

But it's a fundamental problem that we have in climatology is that with all of these adjustments, with stations changing, instrumentation changing, stations coming, going and moving, it really makes it difficult to try to figure out what global temperature really means. Okay, this is fascinating. Thank you for providing this context. It's really helpful. Sure. So when we look at the past and climate change over the years, decades, centuries, what do we know about the natural outcomes of that? And you hear people talk about, you know, we're having more hurricanes, we're having more tornadoes. Do we have historical records that show in the past when maybe the planet did warm that we have.

those same results where there was maybe more natural disasters, those types of things. Yes. In fact, NOAA also keeps track of something called the Palmer Drought Severity Index. And what that just simply measures is droughts and floods. And if you look at that over the last, I think they're running about 120 years now, what you see is a lot of drought occurred in 1930s, the dust bowl, a lot of drought occurred in the 1950s. If you remember back then, it was a very dry period. there's lots of variability in these records, no long-term trend. When we get to hurricanes, we talk about lots of hurricanes coming on. And, of course, as you just mentioned, the media likes to say, you know, we're going to see more of these.

They're going to become more intense. They're going to make landfall more often. No, no, no. They're not becoming more intense. They're not becoming more frequent. They're not making landfall more often. You can see this in the record. I mean, just go back and look at the observations.

The other problem is tornadoes. This is the interesting thing is because tornadoes create a lot of damage, and we want to always say we're seeing more tornadoes. And are we? And the answer is, first of all, yes, we are. We are seeing more tornadoes, but that's because prior to 1990, we had to actually see a tornado for a tornado to be recorded. And so if one small tornado happened in a Kansas wheat field

and nobody was there to see it, it doesn't get recorded. Nowadays we have weather radar. It's almost impossible for a tornado to escape weather radar's view. And so we see more tornadoes as a direct result of the advent of weather radar and lying reless on Jim Smith, who happens to be out in the field, and says, oh, I see one and reports it. So we see that jump, but if you look before the jump and you look after the jump, there's really no trend at all.

And the other interesting thing is if we look at the jump, is if we look at the longer record of the catastrophic tornadoes, the Category 3, the EF3, 4, 5, where they would be, we would see them regardless. The idea is that if you look at those over time, they're actually decreasing in intensity. Now, that's actually expected under a warmer world, because without getting into too much detail,

you know, as the world warms, the polar regions will warm faster than the tropics for a variety of reasons I won't go into. But that reduces the temperature difference between the poles and the equator. And what drives most tornadoes, what drives most severe storms, is that temperature gradient,

where you particularly have warm moist air coming up from the Gulf of Mexico in the United States, colliding with cold, dry air coming out of central Canada. That difference in temperature extremes and also moisture creates rising motion to the moist air,

which gives you a lot of potentially violent storms, lots of precipitation, lots of wind, lots of tornadoes and things like that. Go to a warmer world. The poles warm more than the tropics. We lower the temperature gradient between the equator and the pole. We don't have as strong a contrast between the Gulf of Mexico warm air and the cold air coming out of Canada. And when the two collide, it's not as severe. So we'd expect less severe rainfall events, less severe hail events, and less severe tornado events.

And that's in fact exactly what we're seeing. Fascinating. Okay. So given what we're seeing right now, if and in comparison to what we've seen historically, do we have a sense of how long this current cycle of warming should last, might last before the planet? it starts cooling again. Well, what's likely to drive some of this is going to be solar radiation. The idea is the sun went through a colder period or a limited period,

which was known as the Mondre minimum, the Dalton minimum, when the amount of what we call total solar irradiance had decreased in the 17-1800s, and then we come towards what's a local solar maximum. What the sun's going to do is hard to predict, but solar physicists are starting to imply that we think that over the next 100 years or so, the sun actually may start to wane a little bit. Less solar radiation means less heating. Less heating means less warming, possibly headed back to cooling conditions.

The earth is like a flywheel. It takes a while to catch up to some of this stuff. But nevertheless, they're saying that temperatures should start to go down because the solar heating is going down. whether you can actually predict the sun and the sun's behavior another 100 years in advance is a little bit more difficult, I would imagine, than trying to predict what tomorrow's weather is going to be. But nevertheless, some people are saying it should get colder and we'll have to see what happens. We sure will.

David Legates, thank you so much your time today. Encourage all of our listeners to check out your work at the Heritage Foundation. and we really appreciate your willingness to kick off this climate change series with us today. And just appreciate your insight on this topic. Thank you. And I'm currently working with the Cornwall Alliance for the stewardship of creation. And you can find us online at cornwall alliance.org. Excellent.

Thank you so much. We will leave a link for that in today's show notes. Really appreciate it. Thank you. With that, that's going to do it for today's episode. Thanks so much for being with us for part one of this. Climate Change podcast series. If you have not done so, make sure to take a minute to leave us a five-star rating and review an Apple podcast or wherever you like to listen. And as we kick off

the new year, make sure that you are staying up to date on the news with the Daily Signal top news every day around 5 p.m. It's right here in the same podcast feed. Thanks again for being with us today. Have a great rest of your Wednesday. We will see you right back here around 5 p.m. for our top news edition. The Daily Signal podcast is brought to you by more than half a million members of the Heritage Foundation. Executive producers are Rob Lewy and Kate Trinko. Producers are Virginia Allen and Samantha Asheras. Sound designed by Lauren Evans, Mark Geinney, and John Pop.

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