Interview with Dr. Diana Ürge-Vorsatz of the Intergovernmental Panel on Climate Change

July 10, 2020


Pre-Covid, I had the privilege of interviewing Dr. Diana Ürge-Vorsatz, Professor of Environmental Sciences at Central European University in Hungary and Vice Chari of Working Group III of the Intergovernmental Panel on Climate Change (IPCC). I caught Dr. Ürge-Vorsatz for a Zoom call from India shortly after she addressed an energy conference there. We spoke about her perspectives on Passive House, climate action, embodied carbon, the different opportunities and challenges for Passive House in the global South and global North, and a recent article she co-authored with Amory Lovins of Rocky Mountain Institute.

Zack Semke: I heard rave reviews about your keynote address at the International Passive House conference in China, and I know you also just finished up a keynote at an energy conference in India. Is that right?

Diana Ürge-Vorsatz: Right.

Zack: What is your message at these conferences? Is it similar and, if so, what are you sharing at these events?

Diana: I do try to tailor my message to specific audiences and to the specific geographic location where I’m going, but almost all my talks do start with the climate urgency. While I’m not usually officially representing the Intergovernmental Panel on Climate Change (IPCC) at these talks, I am wearing the hat of an IPCC Vice Chair, so I do start, usually, with the most recent findings from the IPCC. It still is possible to hold global warming under at 1.5° C—but we need absolutely urgent action now, and I support that with a couple of slides from the reports.

Depending on where I go, I also look at the local impacts. For example, in India, I was talking today about how in the reports it states that by the middle of this century we are going to experience, in the tropics climates we have never observed before. That’s very scary, I believe. The tropics are going to be badly affected and crop failures will be an increasing risk, and recent research shows part of this region could become uninhabitable for humans outdoors. I talk about this, but I talk about how it is feasible to still halt it, and what the keys are to this transformation. To every specific audience I try to tailor my message to what they’re most interested in, but typically I do emphasize the importance of energy efficiency first. Also, today, I brought at least two or three major streams of evidence where it’s much easier to deliver climate change mitigation aspirations if we start with improving energy efficiency first. First, we bring down demand, and then supply the remaining lower demand with renewable energy or low-carbon energy. It’s much easier, it’s faster, it’s cheaper, and it brings a lot of co-benefits, as well.

I also do warn most audiences about the lock-in risks, and how to evaluate that and how to avoid it. If it’s a buildings energy audience, I warn them about the importance of emissions in building infrastructure because oftentimes we are only focusing on operational energy and much less on embodied energy, and this embodied energy is becoming more and more important.

I really hope that, finally, the Passive House concept will go over the tipping point and will achieve more mass penetration into the key markets, because that’s really essential for meeting climate goals.

Zack: The embodied carbon question has really risen to people’s awareness and consciousness—probably more in the last year than at any other time. I have sometimes heard folks say that embodied carbon is more important than energy efficiency. I think there’s a little bit of a tendency among some building designers to be willing to move away from energy efficiency and instead focus on embodied carbon, as if it is an “either-or” proposition. Can you say a little bit about what relationship there is between energy efficiency and upfront carbon emissions in buildings? How are they related?

Diana: That’s a very important insight. I have heard about such tendencies or such insights from architects, and certainly the professional community has such impressions, which are probably based on experience or calculations. We do need to take this very seriously. Based on the analyses that I have seen so far, it is true that the more we move towards very low operational energy buildings, embodied carbon becomes more important and embodied energy becomes more important. But it’s only when we move in this direction, when you already have a very low energy building, to really state that embodied carbon and embodied energy is more important. However, I don’t think that we can have a blanket statement because it very much depends on your power use, right?

Zack: Sure, sure.

Diana: …How is it used and what fuels you’re using to generate your building. But I think cannot give a blanket judgment on this right now. For example, I was reminded during this trip to India that cooling energy use here is much more difficult to bring down to very low energy level than heating. Maybe you have more insight, and I would love to have the feedback of your readership, but based on discussions and looking at several case studies in the tropics, I see that while heating demand can be brought down (and I’m not talking about integrating new materials; I’m just talking about building without energy generation) to roughly 15 kWh per square meter per year or even lower in most climates — there’s no way you can bring cooling energy use in high-rise commercial buildings in hot and humid climates down so much. The numbers I have seen, even for certified Passive House, are more like 170 kWh per square meter per year for cooling, which is ten times higher than the cutting edge for heating. So, when you’re talking about that kind of energy use, it would be hard to wash that off immediately, especially if you’re talking about India or China or other places in the tropics where lots of the power right now is still generated with coal. So, right now, I don’t think there’s an easy answer. Also, for some climates and regions, I don’t know what the right solution is for embodied carbon. I don’t think it’s that easy. Like, in India, there isn’t so much land available for primary productivity and there’s limited potential for bio-based materials to replace cement. Finally, our recent major review paper to come out soon indicates more limited impact of carbon storage in building materials than we previously thought. In summary, efficiency remains the pivotal goal in my view.

Zack: That makes sense. I’d love to pivot now to the piece you wrote with Amory Lovins and other scientists around the world for Environmental Research Letters, “Recalibrating Climate Prospects.” It’s a really thought-provoking piece that provides some insights into why we might feel a little bit more optimistic about the potential for mitigation. Could you just summarize what the findings were from that work?

Diana: So, I really need to give the majority of the credit on this paper to Amory because it was his idea and his really amazing analysis. What I have complemented it with is a couple of thoughts and additional analyses, but the thrust of the paper and the key analyses are really his.

But I was so enthusiastic about this. Basically, what he has been showing is that if you really analyze trends that are not often analyzed—so, for example, the rate of increase in renewable energy; the rate of increase in energy efficiency, meaning primary energy intensity decrease. If you look at these trends in the last few years, since 2010, we see a major global shift towards cleaner energy sources and improvements in energy intensity. Now, it’s interesting to add that we wrote that paper a bit over a year ago, and that we did not have the most recent data. Unfortunately, by adding in the 2018 and 2019 data it makes it seem that the world may be slipping back into the trends of the 2000s.

But there are still some really, really impressive figures in the paper. For example, the annual change in additions of non-fossil energy up to 2010 is mostly large hydro and nuclear. However, in the 2000s, nuclear starts to decline and there’s quite a few years where nuclear reactors are taken offline, and then in the 2010s, and since the 2010s all the way until now, there is a very significant increase in solar and wind and other renewables. Taken together, they significantly outpace any of the previous power capacity additions—including nuclear. So that’s really very promising.

Also, Amory shows that modern renewables—which excludes hydropower above 15 MW—surpassed nuclear energy production—not capacity, but production—in 2016. This is difficult because renewables are intermittent; they’re not like nuclear power, which, if it’s there, produces 24/7. Solar and wind are not 24/7. In 2018, they surpassed one terawatt of capacity, which is very significant. Bloomberg Finance projects that just solar alone will have 7.5 terawatts of installed capacity by 2050, which is half a terawatt larger than all of today’s power producing capacity on the planet. And energy efficiency has also been growing at a very promising rate.

If you look at these numbers combined, the rates of improvement are not that far away from the rates of improvement that are needed to meet 1.5° C targets. So, it doesn’t mean that it’s a piece of cake, and it doesn’t mean that we are there at all, but it does show that the world has been developing in a really good direction since 2010, and that we cannot not let this drop. If we just ratchet the trend up, we are really not all that far away from the required rates of increases. That’s basically key deliverable or key message of the paper.

Since 2010, we see a major global shift towards cleaner energy sources and improvements in energy intensity...If you look at these numbers combined, the rates of improvement are not that far away from the rates of improvement that are needed to meet 1.5° C targets. So, it doesn’t mean that it’s a piece of cake, and it doesn’t mean that we are there at all, but it does show that the world has been developing in a really good direction since 2010, and that we cannot not let this drop.

Zack: I really appreciate the summary, and the reminder that despair is premature. Not to say that we’re there, but that there is progress being made. I think sometimes it’s hard to remember that for all of us.

Diana: Of course, The paper came in the right moment because several major U.N. and other reports came out just the week before painting very bleak pictures. The media has largely interpreted this all as the train is gone. Basically, our paper says, “No, it’s not gone yet.” In fact, we just need to speed up a little bit to still get on this train and then just keep speeding up even more.

Zack: Excellent. That’s a good segue into the next question: What is your assessment of where we’re at globally with Passive House? Where are the hot spots? What’s your take of this transition that we’re all so eager to see?

Diana: Well, I really hope that, finally, the Passive House concept will go over the tipping point and will achieve more mass penetration into the key markets, because that’s really essential for meeting climate goals. It’s especially important in the global North. There’s really no reason, in the global North, why Passive House shouldn’t be happening for new construction. For retrofits, we are a bit more behind. We just need a couple more key demonstration buildings and I believe we need more simplified solutions to reduce the hassle factor and drive costs down. Whenever you are at the beginning of a technology, there’s always significant improvements to be made.

In the global South, it’s really in a much more immature phase, and I hope that this technology will make inroads faster into these markets, as well. In my understanding, Passive House is the building method that can deliver the biggest savings in operational energy, even for cooling-dominated climates, which is really the key. Cooling energy use is already being affected by climate change and this is all exacerbated by the fact that these regions are where affluence and floor space and comfort are all going up. Even without climate change, the demand for cooling increases. How we build this enormous amount of new infrastructure will lock us into a future and determine these emissions for decades or centuries to come.

However, as mentioned, our review paper on this topic on which we have worked with a handful of industry and academic leaders for close to two years, is coming out very soon in Annual Reviews in Environment and Resources, so everyone can find out more on the scientific assessment of these trends.

Zack: I’m very grateful for your work in this area. And I really appreciate your taking the time to speak with me.


Zachary Semke
Zachary Semke
Zack Semke is Director of Passive House Accelerator and a member of Al Gore's Climate Reality Leadership Corps. He writes and speaks about…

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