Global Climate Change

Interview with Richard C. J. Somerville

Richard C. J. Somerville is a professor of meteorology at Scripps Institution of Oceanography, University of California, San Diego. He is a Fellow of the American Association for the Advancement of Science (AAAS) and the author of the award-winning book The Forgiving Air: Understanding Environmental Change. Somerville has also briefed UN climate change negotiators and advised federal agencies on education and outreach. He holds a PhD in meteorology from New York University.

Please briefly describe your organization/institution.

Scripps Institution of Oceanography is both a university department and a large research institution at the University of California, San Diego. Although it is called Scripps Institution of Oceanography, and marine science has always been the main area of expertise here, Scripps now essentially covers all of earth sciences, including geology, geophysics, etc. There is a big group of people here working on climate, including atmospheric scientists like myself.

Some scientists have been claiming that global warming does not exist. How would you respond to that claim?

First, you have to define your terms. Global warming is a handy catch phrase, but it is more of a journalistic term than a scientific term. The larger question is whether climate change is occurring. The answer is yes, of course, it has always occurred and is always occurring. However, global warming usually refers to the question of whether we have detected a trend in recent years in climate that is attributable in whole or part to human activity, in particular adding greenhouse gases, like carbon dioxide, to the atmosphere. The answer there is that the climate has certainly been warming over the last century, and in particular over the last two to three decades. There is strong evidence, from the reliable global network of thermometers, that climate warmed during the first 40 years or so of the 20th century, then cooled slightly from about 1940 into the 1970s, and since the 1970s has been warming rapidly. The climate on global average is now about 6/10º C warmer than it was 100 years ago. The1990s is the warmest decade in the modern record, and all the warmest years of the 20th century occurred in the 1990s. When we graft that instrumental record onto the earlier record from proxy data, from things like tree rings, then it seems quite clear that it is not only warmer now than it is likely to have been over the last several centuries, but the rate of warming over the 20th century has also been unprecedented within the last 1000 years. Therefore, the great majority of scientists would say that, yes, there has been global warming in that sense, and, furthermore, we see a lot of other evidence of climate change, including the retreat of mountain glaciers and the thinning of sea ice. Taken all in all, there is considerable evidence that the climate has changed. An overwhelming majority of experts would also agree that the change has been one that cannot be entirely accounted for by natural causes, so that to account for this climate change that we observe, one has to invoke human activity as a partial cause.

The metaphor that I use in my book is that people have always been spectators at the great natural pageant of climate change, but now we are actors as well—we have come up out of the audience onto the stage, and we are in part responsible for the change.

Do you believe that the United States should ratify the Kyoto Protocol? What are some of the advantages/ disadvantages of doing so?

The short answer is yes. The longer answer is that the Kyoto Protocol is a minor step in the sense that it does not stabilize the total amount of greenhouse gases in the atmosphere--it just puts a limit on the rate at which they are being added to the atmosphere. In other words, the Protocol is a restriction on emissions, not on concentration. Furthermore, from the point of view of the atmosphere, it is a rather smallish step, because it is an agreement to reduce emissions to only a few percent less than they were in 1990. If you run the numbers and look 30 years out, it makes only a tiny difference to the concentration whether the Protocol is signed or not. If everyone signed it tomorrow morning and nobody cheated, you would still be adding carbon dioxide, and all the other gases covered by Kyoto, to the atmosphere; you would just be adding them at a somewhat slower rate than what you might have otherwise done. That very fact has been central to an argument made by some opponents of the Protocol, who say that it is going to cost money to implement the Protocol, it will throw some people out of work, and it will cause the US some economic hardship. Furthermore, these people point out that the Kyoto Protocol is unequal, because it does not make demands of developing countries in the same way it does on developed countries, like the US—all of which is true.

My reason for supporting the Protocol and advocating that it should be ratified by the US and come into force is that many similar international agreements have had a tortured history. They tend to begin with imperfect steps that at least bring the issues to the table, get countries seriously talking about them, raise the political and public profile of them, and eventually lead to better and more workable agreements. They are a starting point, and they are not the final solution to solve the global climate change issue. They at least make it more likely that important countries like the US, which is the leading CO2 emitter and has the technical and financial wherewithal to make a difference, will be brought to the table—making it less likely that they will turn their back on the issue.

I think you can draw many parallels. For example the issue of the ozone hole, which is often thought of as a paradigm for this one, was a problem that was not solved by the initial agreement. Ozone depletion was predicted by scientists, the ozone hole was discovered, research was done, chlorofluorocarbons were found to be the culprit, and the Montreal Protocol was the international agreement that started the phase-out of their manufacture. The Montreal Protocol, however, was followed by other international instruments that were signed in London, Copenhagen, and elsewhere, which accelerated the timetable for the phase-out and added additional ozone-depleting substances to the list. In some sense, if the ozone story is a success story, as I think it is, this is not because an agreement was signed in Montreal; it was because that happened first, and then many other things happened as a result: industry got more involved, people cared more, politicians responded to the pressure of voters, and so on.

Therefore, I would argue in favor of the Kyoto Protocol, despite all its flaws, including the fact that it, by itself, is not going to stabilize CO2 concentrations. Remember that the UN Framework Convention on Climate Change, which came from the Rio Earth Summit, and to which the US is a party, has as a goal stabilizing the concentrations of greenhouse gases at levels that are not dangerous to the climate, without prescribing specifically what those levels are. The Kyoto Protocol is a tiny step toward this ultimate goal.

I think you cannot undervalue these tiny steps, because once a government, the US for example, admits that climate change is important, and acknowledges that it is not going to go away, that this is something serious that we have to do something about, and signs and ratifies such a Protocol, then one has suddenly raised the stakes. Nations can then follow that up with sincere, meaningful actions, such as helping industry work on fossil fuel substitutes, and motivating people to do the win-win things that everyone is in favor of, such as improving energy conversation and energy efficiency, which have many side benefits as well as slowing the emissions rates of CO2. Kyoto is, therefore, an important first step. Furthermore, it is the only game in town—that is to say, there is not an array of, say, six treaties on the table, one of which we might sign, and five of which we might reject—it is the one.

This is an inherently international problem. CO2 flows across borders on the wind. The climate responds to the sum of all the CO2 added to the atmosphere, globally. Therefore, in order to have an impact on all the nations of the world, which is absolutely necessary, then the leading nations have to exert a serious kind of leadership, which the US has not shown much willingness to do so far.

President Bush released an initiative as an alternative to the Kyoto Protocol. Do you believe that his alternative is more or less effective than the Kyoto Protocol in combating global warming?

It is not effective at all. In essence, it does not require the US to do things that would not have happened anyway; the greenhouse gas "intensity" (the amount of greenhouse gases emitted to produce a given amount of energy or a given increment in gross domestic product) is going down anyway as a result of technological progress. Such initiatives probably would have little or no effect at all in that sense.

The Bush Administration has said from the start that it thought this was an important problem. I applaud that. Consequently, I think when both the White House and Congress announced they were not interested in the Kyoto Protocol, one naturally expected something serious to emerge as an alternative, but so far this has not been forthcoming from either side. For example, the McCain-Leiberman global warming bill was defeated in 2003, which is an example of Congressional reluctance. An energy policy focused overwhelmingly on increasing energy production is an example of Administration inaction.

You can argue against the Kyoto Protocol with its cap-and-trade approach, with targets and timetables and so on, but we do not yet have significant options on the table aside from these approaches. Furthermore, we are now seeing many other countries seriously engaged in the Kyoto process, as well as seeing large multi-national corporations which have mounted Kyoto-like programs internally. Part of this effort admittedly may be green publicity, but nonetheless it is a consciousness-raising activity. I think there is a lot to be gained from that. Keep in mind that the low-hanging fruit, the things that are easily done and that will make a real difference, because they do result in reduced emissions, also have concomitant benefits. They are win-win. As a small example, if you buy a more fuel-efficient car, this helps the climate problem a little. But think of all the other things it does—it puts money in your pocket, it helps the balance of payments, it reduces America's dependence on foreign oil, it may even improve international security. After all, there is no reason for you not to want to spend less money on energy. All of these kinds of actions are helpful on other grounds, quite aside from the benefits for the climate problem.

How might global warming affect the US as opposed to Europe or Asia? What would be some of the various regional impacts of global warming?

Some things are obvious, and some things are not so obvious. One of the surest consequences of a warming climate is rising sea-level. This is complicated and occurs for several reasons. One is that the ocean thermally expands; the same mass of water takes up more volume when it is warmer than when it is cooler. Another is that you have more water in the ocean, because some of the ice that is on land melts and ends up as liquid water in the ocean. In fact, sea level is already rising slowly at a rate of perhaps 6 inches per century. However, it is likely that the rate of rise will accelerate as the climate warms, and the potential rise is very large. In the ice ages, when the oceans shrunk because it was colder and some of the water ended up frozen on land, the sea level was much lower than it is today, not by a few inches, but by many tens of meters. The nations most affected by rising sea level are those with vulnerable coastal areas. If you go to the UN climate change negotiations, as I have, the nations there that are the most vocal and the most concerned about climate change are the small island nations, which in many case feel their very existence is threatened by rising sea level. This is an example of special geographic circumstances, which cause these countries to have an especially acute concern about climate change.

Aside from that, it is safe to say that, when confronting climate change, as with all changes in the environment, it is better to be rich than to be poor. A wealthy country will have many resources, including an infrastructure and an intellectual talent base, with which to cope with climate change. In many cases, Africa seems likely to be the most severely affected continent, because it contains many relatively poor developing countries, and because in Africa one finds a high level of subsistence farming and many regions that are already water-limited. Thus, it is likely that, if the pattern of precipitation changes, Africa will be especially vulnerable. One must realize too that African agriculture in general will not have the resources to deal with climate change to the same degree that, say, American agriculture might. A wealthy developed country such as the US can rely on irrigation, fertilizers, pesticides, alternative crops, and so on.

However, there may be some winners. For example, Canada and some countries in Northern Europe may see their growing seasons extended somewhat; we already know that spring now effectively comes earlier in the year than it did several decades ago. If you think of your country as too cold on the whole, then it may help to have a growing season that is longer. Aside from these examples, it is very hard to generalize about the effects of climate change, but experts agree that losers will outnumber winners.

I do not like the term "global warming," because climate change is much more than warming and because what happens globally is not so important as what happens locally. In fact, when you mention a global warming of one to five degrees, which is the range of possibilities that one talks about over the next several decades, then people often think that that is a rather smallish amount. However, most people do not realize that a few degrees averaged globally has huge consequences. For example, the ice ages were only a few degrees colder than the climate we have today, so globally averaged temperature is a very inadequate measure of the severity of climate change. Much more important consequences of climate change would probably include changes in phenomena such as occurrences of extreme weather, patterns of precipitation, hurricane characteristics, El Niños, and storm tracks. Predicting such things with confidence is not yet possible, but there are many reasons to think that these aspects of climate will be different in the future. We know, for example, that it is highly likely that in a warmer world, patterns of precipitation will change.

A specific phenomenon that is likely to affect the US, and which is an object of active research as we speak, is the possibility that the climatology of hurricanes might change as the climate warms in coming decades. Hurricanes are creatures of the warm tropical oceans; they do not form when the sea surface temperature is below a threshold critical value. Examples of research questions now being asked are, in a warmer world, will hurricanes be significantly different from today? Will the hurricane season be different? Will the geographical area that is vulnerable be different? Will the strongest hurricanes be stronger? The honest answer is that we do not know the answers to these kinds of questions yet, but there is plenty of reason to suspect that there will be changes, even if we cannot predict them today. We think that these changes may depend sensitively on the circulation of the atmosphere and on the temperature of the ocean, both of which are likely to change when climate changes.

Thus, you march from rather sure things, like rising sea level, on to things that are more uncertain. I think that the pace of climate change is a concern as well. As I said, climate has always changed, but it is changing more rapidly now than it appears to have changed in the recent past—making it harder for adaptation to occur, whether you are farmer in Africa or a migrating bird that expects to find a given food supply at a given time of year along your flyway.

For that reason, although you can find examples of winners, when you count up the winners and the losers, adapting to a different and rapidly changing climate tends to be more costly than beneficial.

Has scientific research shown any leads as to what might be the best alternative to the burning of fossil fuels?

I do not know what the best alternative will be. I don't think anybody does. I am suspicious of people who seem very certain and who place all of their faith in one possible alternative or another. I am a technological optimist, but I am skeptical of people who think they can guess what technology will do in coming decades. There is no reason to think that our grandchildren in 2050 are going to be using the same array of technology that we have now. On historical grounds alone, I have great faith in the rapid advance of technology and also in its unpredictability. I cannot tell you if we will have a hydrogen economy fifty years from now, but I do think it is important to pursue many different possibilities.

For example, there is a whole suite of renewable energy resources, but even combining all of them together, today they are not a big fraction of the US energy mix, nor of the global energy mix. In part, that is because they have not yet been developed as fully as they can be, and part of the reason for that is the many subsidies, both overt and hidden, that favor fossil fuels. I do think it is very important to work on alternatives, and especially to motivate the political leadership in a powerful country such as the US to work on this important issue.

The other issue that is very difficult for people to come to grips with is population, which is the basic driver behind much of global climate change and, more generally, environmental change. Many people do not realize that we have tripled the world's human population in about the last 70 years, from two billion people in 1930 to more than six billion people on earth today, and it is still growing. It is growing globally, mainly in developing countries, and all those people have aspirations. The US population is also growing.

Consequently, one has to come to terms with the idea that you cannot have an unlimitedly large human population. It becomes a question not only of how many people can the earth support, but also a quality of life issue. This topic is very tough to talk about, because it touches people's moral values, their most personal decisions, their socio-economic status, their cultural heritage, and even their religious convictions. But I think in the long-term, population is an aspect of climate change that you cannot escape from, because it is the fundamental multiplier.

That is why I believe that this is not an issue where governments solve the problem or governments talking to scientists like me solve the problem. Instead, I am convinced that the problem will be dealt with adequately only when society as a whole becomes involved.

Is there a role students can play regarding global climate change?

Yes, of course. This is a problem in which all of humankind has a role. I think one thing that students can do is to work to insure that this issue becomes prominent and stays prominent. There are lots of things that ordinary people have to worry about when they get up in the morning, and climate change may not be on the top of everybody's list. Therefore, there is a real need to make people aware of it in a serious way. Simply talking about this issue and bringing it to the attention of politicians, so that they are forced to confront it, is important. This is especially so in the advanced western nations. I have great faith in the ability of democratic governments to respond to the concerns of their electorates. I think that working to maintain this issue as a high priority in the public and political consciousness is an important step.

Aside from that, I think climate change is typical of a number of modern problems in that it has a strong technical and scientific component to it, and many people including politicians are, unfortunately, just not comfortable with scientific issues. To be blunt about it, there is a widespread degree of scientific illiteracy in the world today that is simply not laughable any longer. Making decisions about many issues, the environment being one of them, requires a level of familiarity with scientific and technological topics that many people just do not have, and this has profound consequences. For example, it makes it easier for clever disinformation campaigns to confuse people. If you walk down the street and ask questions, you will find that many people are sincerely concerned about the environment, but they are generally poorly informed and not knowledgeable on even the simplest factual matters. In a recent Congressional debate on global warming, Senator James Inhofe (R - OK) said that climate change is a scientific hoax, apparently refusing to believe any of the science of climate change. This is unacceptable. I think students today can help combat that sort of ignorance. It is not necessary that everyone become a scientist, but what the world needs is people who understand something about science and the scientific process, so they can make an informed judgment when issues like this come up.

Submitted by: Liz Walsh, former Education Program Coordinator, SPUSA