“Any information about the future has a large economic value” (Carlo Buontempo, C3S)

How realistic is a temporary “overshoot” of the Paris Agreement’s 1.5°C limit, followed by a return below it?

The overshoot is basically a done deal, in the sense that there is no credible, physically plausible scenario under which we won't exceed 1.5. That's also what the United Nations stated at the beginning of September. In all likelihood it will happen in the next few months or years, but possibly this side of 2030. So we are effectively in overshoot territory, or will soon be.

The question is how to manage the overshoot. It's still possible, although very hard, to come back below 1.5 at the end of the century. That objective is not gone, but it is very difficult to obtain. What the report calls for is a sense of realism. This is happening, and it's up to us to manage the overshoot. What is absolutely clear is that 1.6 is better than 1.7, or better than 2. Every tenth of a degree matters. And the information that Copernicus or other international providers of climate information provide is vital for that management.

The Niño 3.4 region hit an all-time monthly high of 29.70°C, above the peaks of 1982/83, 1997/98 and 2015/16. What do you expect in the coming months, and what are the implications for agriculture, energy and food security?

There are two elements here. The first is that the El Niño record is not just due to the fact that it is operating in a warmer world. At the moment, we are reaching the highest temperature for the ice-free seas, 60 north to 60 south. Given that El Niño adds to that, you would expect an El Niño operating in a warmer world to reach a higher temperature.

But this El Niño, in its own right, is a very large event, independent of climate change. Its amplitude in the 3.4 region, relative to the rest of the tropics, is already at the very top of what we have seen in the past. The current seasonal predictions suggest we could reach around 3.8 by late November or early December, which is very high for that region.

We have seen very few such large events, if any, so the past is not necessarily a good proxy for this year.

Drawing firm conclusions about the implications is more difficult. The impacts on the Pacific region are better understood and stronger than elsewhere: the disruption of the monsoon in India, the drying of Indonesia and of northeastern Brazil. But we have seen very few such large events, if any, so the past is not necessarily a good proxy for this year. One of the best things we can do is look at what the seasonal predictions tell us: the output of the multi-system prediction that Copernicus makes available to everyone.

For Europe, the predictions call for a higher than usual chance of warmer temperatures, certainly until Christmas, so the odds are on a milder autumn. For precipitation, the beginning of autumn will increase the chances of wetter conditions over the Mediterranean and the Middle East. From November onwards, the chances of a wetter winter will move north: the region that has experienced drought in recent months, from the UK to Poland, has a higher than usual chance of wetter than usual conditions.

Record-low flows on the Rhine, Danube, Vistula and Garonne-Dordogne disrupted navigation, water supply and agriculture. How prepared is Europe for prolonged droughts, and how does that square with the floods in France and Spain?

On the one hand, we know from the physics that the hydrological cycle is speeding up, which means that the intensity of the most intense precipitation is increasing. This is what the hydrometers are telling us. On all continents, we have seen it.

The flip side is that we also see an increase in drought conditions and in the intensity of drought. Both sides of that strange equation are going up.

Europe is doing a lot. Some calculations suggest that something short of 100,000 lives have been saved because of the interventions different countries have taken in managing heat waves. For drought and water resources, we have to take the same approach. We are living in conditions fundamentally different from historical conditions. Still, it’s not enough, because the changes are so large that it requires a rethinking of our environmental risk assessments.

How can businesses, banks and insurers use Copernicus data, which is free and open, to assess physical climate risk and plan their transition?

My strongly held belief is that any information about the future has a large economic value, and we know quite a lot about the future. Any clever economic actor should look carefully at this information, because it can save lives, money and property. And many are already doing it.

The big adopters of our data are large energy companies, insurers and banks. We have now developed a climate set, a portal of climate information that the European Investment Bank will use to monitor the climate risk of its investments, which goes live in November. Many other actors, from central banks in Europe to some private banks, are looking at this as a starting point for their evaluations. Seasonal prediction has that value even more, because it has the power of modulating gas price risks or water resource risks.

What are the current limits of the observing system (coverage, uncertainties, differences between datasets such as ERA5 and others) that readers should know about?

The first thing to know is that we are very fortunate to live in these times, although it may sound strange: no other humans before us have had so much information about our climate. It’s incredible what we can observe from satellites, what we can model, and how well we can interface data from different continents. It’s a huge common resource for the common good.

That being said, there are things we cannot observe, even with the best of our technology. The deep ocean, for instance, is a blind spot. Satellites do not reach it, so we are largely blind to what happens there. We have to rely on submarine drones that emerge every now and again and send us information.

Even for permafrost, we can only get information on the top layer, and relatively little on what happens underneath.

Surface hydrology is probably one of the most important variables for the impact of climate change, since most impacts are mediated by hydrology in some shape or form. Still, our near-real-time understanding of the amount of water flowing in global rivers is very inaccurate and incomplete. Stations monitor some rivers and satellites monitor the very large ones, but for all the rest we are quite blind.

So while we can observe much more than ever before, this doesn’t mean that we can observe everything. We need fundamental research to improve our understanding of some of the key components of the global climate. The Global Climate Observing System (GCOS) lists 54 essential climate variables. For only 33 of them can we currently generate a climate data record, so 21 are, to some extent, beyond our reach.

What investments in observation and modelling are needed for the next round of climate decisions, and where does Europe stand?

We need fundamental research and innovation, because that’s how you crack the hard problems to some extent. Measuring the deep ocean is technologically very difficult and requires creativity, innovation and invention. We are already investing, but we should keep investing and possibly increase it.

We also need continuity of funding for operations. It’s not enough to have a great measurement concept flying on a one-off satellite. You want a series of satellites that fly on a regular, predictable schedule and provide data day in, day out. Copernicus has been a bit of a game changer, even with respect to our American counterparts. There are beautiful sensor missions and models in the US that have pushed the science ahead, but more often than not they lacked sufficient continuity. In Europe, at least for the time being, we have that continuity. If you have a small business and want to run on the back of Copernicus data, you know you can rely on it, because the data is here today and will be there in 10, 20 years’ time.

To conclude, I just want to stress how incredibly valuable this free information is: it’s an invitation to take advantage of a large public investment that can make our lives safer, save money, and promote European leadership and independence. We are ahead of the game in many respects, and we should double down on that.