A decade ago, nearly every country in the world adopted the Paris Agreement, which aims to limit the rise in global warming to well below 2 degrees Celsius by 2100.
Member nations are required under the legally binding treaty to submit every five years their climate action plans, or Nationally Determined Contributions, that detail the voluntary actions they commit to take to cut their carbon emissions.
The treaty couldn’t have come at a more urgent time.
Last year was Earth’s hottest year on record, including the first year to exceed 1.5 degrees Celsius above pre-Industrial levels.
Still, the Paris Agreement has allowed countries to make some modest progress on cutting emissions and slowing the arrival of the 2 degrees Celsius tipping point that experts warn could trigger irreversible and catastrophic climate change impacts.
But a new study led by the University of Washington found that those carbon-cutting gains are not great enough to offset the environmental costs of global economic growth, which has risen sharply over the past decade.
The study also projects how President Donald Trump’s decision to pull the U.S. out of the Paris Agreement for a second time may affect the collective, international effort to fight climate change.
Adrian Raftery, a professor emeritus of statistics and sociology at University of Washington, joins us for more details.
Note: The following transcript was transcribed digitally and validated for accuracy, readability and formatting by an OPB volunteer.
Dave Miller: From the Gert Boyle Studio at OPB, this is Think Out Loud. I’m Dave Miller. A decade ago, nearly every country in the world signed on to the Paris Agreement, which aimed to limit the rise in global warming to below 2 degrees Celsius by the year 2100. The urgency is obvious. Last year was the hottest on record and the first one to exceed 1.5 degrees Celsius above pre-Industrial levels. Few days go by without reports somewhere in the world of deadly flooding, fire, drought or heat.
A new study led by the University of Washington looked into the results of the Paris Agreement. Researchers found that countries did become more efficient and more reliant on renewable energy. Nevertheless, overall emissions kept climbing because global economic output grew faster than those efficiency gains.
Adrian Raftery is a professor emeritus of statistics and sociology at the University of Washington. He is the lead author of this new study, and he joins us now. It’s great to have you on Think Out Loud.
Adrian Raftery: Great to be here. Thanks for having me.
Miller: Can you give us a sense for what countries – developed or developing – are supposed to do, what they agreed to do under the Paris Agreement?
Raftery: Well, the Paris Agreement was an effort to keep global temperature increase to 2 degrees Celsius – that’s about 4 degrees Fahrenheit – by the end of this century, and it was to be achieved by international cooperation. So almost all countries made promises to reduce or limit their carbon emissions until 2030, in most cases, and it was up to them to decide how much that would be by. Different countries promised different amounts, but the cuts promised were pretty substantial.
Miller: Just to be clear, though, we’re talking about goals here, or promises, but not mandates, right? There are no international penalties if countries don’t meet their stated goals?
Raftery: That’s correct. There were no actual sanctions or penalties. They were voluntary targets, which is quite unusual, I think.
Miller: How well have individual countries done in terms of their own goals?
Raftery: Well, there were two kinds of goals, which makes it a little complicated. The goals of mostly developed countries were to reduce total carbon emissions by substantial amounts, which were typically around 30% or so, over the period up to 2030. And then there were other countries, mostly developing countries, whose promises were to reduce carbon intensity.
Now, carbon intensity means the amount of carbon emissions per unit of GDP. And the difference between these two was that the developing countries basically allowed themselves to catch up in terms of economic growth, in terms of GDP, because the developed countries had been the ones that made the biggest contributions to carbon emissions in the past, and the feeling was that they should bear more of the of the brunt. So that gave a bit more leeway to developing countries.
Overall, this is what we found: If you look at carbon intensity, by and large, the carbon intensity improved a lot over the past 10 years. Our study looked at what had been done since the Paris Agreement was signed in 2015 – so basically the past 10 years, or at least nine years that we have data for – and we found that carbon intensity actually declined, which means improved by a lot, very close to what the targets actually implied worldwide. So, if you aggregate up all the so-called nationally defined contributions, which were the promises made by countries, they would have implied a 31% improvement over these nine years. And what actually happened was a 25% improvement in carbon intensity.
But the catch is that when we look at carbon emissions in total, they didn’t improve. In fact, they didn’t go down. Not only did they not go down, but they went up by about 6% worldwide. And that’s a very puzzling thing. How could you have a big improvement in carbon efficiency and yet have carbon emissions going up? And as you said in the opening, the reason is because economic growth, or GDP, increased so much. So, over the past 10 years, carbon efficiency or carbon intensity improved by about 3% a year, whereas in the period before, from 1960 to 2015, it improved by only 1% a year. So, the improvements in efficiency were three times higher in the past 10 years than they had been before.
But in total, carbon emissions, there was actually an increase of almost 1% a year. And the GDP, the past 10 years has been a period of rapid economic growth worldwide. GDP increased by about 4% a year, which was much faster than the previous average of just under 2% a year.
Miller: Let me make sure that I understand this and make sure that our listeners do. So when you talk about carbon intensity, is this a fair way to think about it … that it’s essentially a huge, all-encompassing measure of the amount of, in this case, greenhouse-gas spewing stuff that is directly tied to our economic lives, to the making and selling of stuff? And we’ve gotten a lot better at that. It’s just that, because we’re making and buying and selling so much more stuff, because GDP globally has increased, it hasn’t made up the difference. Is that a fair way to put it?
Raftery: That’s exactly right. And actually, you’re absolutely right to say that carbon intensity, it’s one measure that covers a multitude. If we think about it, I have an analogy here: Say a toaster factory, you go back to 1960, it wasn’t very efficient, then manufacturing was made more efficient, so that reduced carbon intensity. Workers, for example, suppose instead of driving their own car, a worker goes to work by electric car or maybe by transit – that improves carbon efficiency. If the factory puts solar panels on its roof to produce some of the electricity it’s using, that improves carbon efficiency. And other technological improvements generally improve carbon efficiency.
So, for example, up to the 1990s, we were using standard light bulbs and then LED light bulbs were invented, which became commercially widespread. That reduced the carbon emissions from lighting by about 90%. So that would have improved the efficiency of the whole economy, including our toaster factory. And then regulations or public measures that mandate or encouraged these developments, like legislation or tax incentives would also have accelerated and encouraged that process.
Miller: But then on the other side, you may have hundreds of millions of newly middle-class people all across the world who are getting toasters for the very first time.
Raftery: Exactly. And that’s really part of what’s happening.
Miller: Let’s turn to some specific times and countries here, because in the nearly 10 years that you were looking at, there was a global pandemic right in the middle. What impact did the pandemic have on these two pieces – on carbon intensity and on overall emissions?
Raftery: Well, that’s really a great question. I’ve been sort of optimistic because actually, during the first year of the pandemic, maybe the first two years – 2020, 2021 – carbon emissions went down a lot. And some people, including myself, had hoped that maybe we could realize that and make that reduction permanent.
But really what happened after that is we just got out of the pandemic and economic output and carbon emissions just sprang right back to where they’d been. So it was really a blip that didn’t really help much at all, unfortunately. I thought it was an opportunity, but it’s an opportunity which we, as a society and indeed as a world, really missed.
Miller: What countries have done particularly well in terms of reducing actual emissions?
Raftery: The countries that have done the best are the European countries, the European Union overall. And we particularly studied Germany because Germany is, I think, looking at the United States, it’s not too dissimilar from the United States. It’s a big, rich country, people live very well and so on. And it’s one of the biggest, I think the fourth [largest] economy in the world. Germany did extremely well. Their total emissions declined over that decade by 28%, whereas their promises implied a reduction of only 9%.
So Germany really did very well, and their carbon intensity also improved dramatically. Other European countries, like France, also did very well. The United States also did well relative to where it had been, and the U.S. is almost on target to meet its commitments as well.
Miller: That’s a striking thing to hear, given that, as I imagine many of our listeners remember, President Trump officially took the U.S. out of this agreement twice. One, soon after it was initially signed when he took office the first time, and then the second time he took office, just nine months ago. So despite that, the U.S. has basically met its pledges?
Raftery: Pretty much, yes. And I would temper that by saying that you also have to look at the absolute levels. The United States, its carbon intensity, carbon emissions per person, are about twice those of Germany. And because it has higher GDP than Germany per capita, its carbon intensity is about 50% higher than that of Germany.
So the U.S. has almost met its commitments, but it’s still way behind other developed countries, if you will, in terms of carbon performance. But it is true, it has come close to meeting its own promises under the Paris Agreement.
Miller: I’m glad I just mentioned your statistics background, because I’m wondering – and hopefully you can explain this in a way that makes sense to those of us who are not deep stats heads – how you do this kind of an analysis and actually separate out for the effects of this agreement?
In particular, I’m wondering if there have been, at the same time, say, efficiencies in new technologies? If wind or solar power are getting cheaper and if the market itself is pushing us globally in a particular direction away from coal or natural gas, how can you say these are the effects of the agreement, as opposed to, this is what was probably going to happen anyway?
Raftery: Well, that’s a really good question. And unfortunately, the simple answer is I can’t for sure, because it’s a very complex thing and there are, as you say, all kinds of things at work here, including technological improvements and so on.
On the other hand, previously we looked at the period from 1960 to 2015, and there were certain trends and there was a steady improvement in carbon intensity over that period, which was not due to the Paris Agreement. And international agreements – there had been the Kyoto Agreement, but it had far less teeth and impact than the Paris Agreement. Then we look at what happened in the last 10 years and the improvement in carbon intensity was a lot bigger than it had previously been. And since the goal of the Paris Agreement was to improve on that dimension, it seems our results are certainly consistent with the idea that the Paris Agreement had a substantial impact, but they don’t prove it, absolutely.
Miller: OK, so what we’re looking at here is a lower rate of emissions increase, but they’re still going up over the last 10 years as opposed to going down – the ultimate goal of this accord. What does that mean for the probability that globally, as a species, we will push past various global temperature benchmarks?
Raftery: A lot of this work internationally – research and so on, analysis – is done with the year 2100 in mind. So the goal, for example, the 2-degree Celsius goal is for the year 2100. When we did the analysis 10 years ago, the projected temperature increase, based on the methods we used, was 2.6 degrees Celsius. And now that has come down to 2.4 degrees, projecting forward on current trends.
But if the NDCs, the promises by countries are met, it would go down. In fact, if they continue past the end of the current Paris Agreement, which is 2030, then the projection would be 2.1 degrees Celsius. So we wouldn’t be too far away from that two-degree threshold if all the promises are met and they continue for the following 70 years.
Miller: That second criterion that has to be met, how likely is that? I know we’re talking about 180-something countries, so it’s so many individual decisions. But when you look at the biggest countries, and the political trajectory and economic trajectory of them, does it seem reasonable to assume that many of them will stick with these voluntary promises?
Raftery: Well, that’s a very good question. And I think to some extent, the reason that the promises have been in the past 10 years – at least in terms of carbon intensity – have been largely met is that climate has been on the world’s agenda and a lot of countries have felt pressure to at least try to meet their promises, even if some of them have not have not quite come up to par. What happens after that, I think, is a political question. And if there is an international will to do that, then I think there’s a very good chance it would happen.
Right now, there’s a bit of a dip in American determination to do that, because of the election of President Trump, who’s not favorable to fighting climate change. But I’m working in Europe right now and there it seems to be as much on the agenda as previously. And from what I see in the media, in China, it is on the agenda.
That’s actually extremely important because China is by far the biggest single emitter in the world; almost a third of the world’s emissions come from China. Their carbon intensity is about three times bigger than Germany’s [and] it’s about twice that of the United States. So, what China does is going to be really important.
And I just add something, maybe that seems ironic in light of what I’ve said, that China produces a lot of stuff and often in coal-powered factories, which emit a lot of emissions. And here in the United States, for example, we buy a lot of stuff, a lot of which comes from China. So reducing that could be one way to reduce American emissions. Ironically, given President Trump’s general approach to climate change, the tariffs he’s proposing or implementing on China could actually reduce the carbon emissions in both countries. So, I know that’s not his intention, but it might be the effect of some of what he’s doing.
Miller: Just briefly, you are working in Europe right now, in Italy, with colleagues there. I’m curious what you’re hearing from fellow researchers, or just Italians or Europeans, about the U.S. not just pulling out of this agreement for the second time, but actively trying to go in the other direction, and being a kind of gleeful and very lonely climate denier on the global stage.
Raftery: Yes, I mean, it’s hard to… I’m just here in Italy for a month. Before that, I was in Germany. I’ve been surprised that it seems like the tenor of the European discussion and debate hasn’t been very influenced by President Trump’s comments and public positions.
For example, when I was in Germany, I was in Hamburg, and in the city of Hamburg, they had a referendum to bring the legally mandated date for having zero emissions, zero net emissions, back from 2045 to 2040. And there’s a lot of opposition to that because it’s economically challenging. Nevertheless, it was passed by a serious majority, even though most of the opinion leaders in the city were against it. And that was a very active debate. So that’s just something I observed.
So it seems that Europeans remain pretty committed and they’ve achieved a lot because, as I mentioned, the carbon emissions in Germany per person, to take the biggest single example, is only about half of the United States. Sometimes it’s asked what we should do, and one kind of flippant but not totally ridiculous answer would be to say, “Do what the Germans do.” They use transit a lot more, their houses are smaller, but just being there, you can’t see that there’s no particular indication that they live worse than Americans, in fact. They seem to live just as well as we do, but they emit a lot less than we do.
Miller: Adrian Raftery, thanks very much.
Raftery: Thank you. Thanks for having me.
Miller: Adrian Raftery is a professor emeritus of statistics and sociology at the University of Washington.
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