The Austrian daily newspaper Der Standard (Karin Krichmayr) from Vienna interviewed climate researcher Anders Levermann. In the following the English translation.

The Earth is heading toward a “free fall” in the face of the climate crisis. It remains unclear what consequences the expected instability will have. The increasing unpredictability of weather and climate poses a threat to society and the economy, writes climate researcher Anders Levermann in a current commentary in the journal Nature.

The physicist from the German Potsdam Institute for Climate Impact Research (PIK) has long been concerned with tipping points in the climate system—those critical thresholds that, when exceeded, trigger irreversible processes that amplify climate change. In the interview, the co-author of the World Climate Reports (IPCC) talks about a system beginning to go haywire and about necessary structural change.

STANDARD: Europe is experiencing an unprecedented series of heat waves and temperature records. Is this already a sign that the planet—as you have put it—is heading toward a “free fall” in the face of the climate crisis?

Levermann: This hasn’t actually been thoroughly investigated yet. What we’re observing is a sharp increase in weather extremes and fluctuations due to climate change. Colleagues from London have already shown that the recent heat wave would have been extremely unlikely without human-caused climate change. But what we’ve hardly investigated so far is whether such developments are already linked to tipping processes.

STANDARD: What exactly do you mean by “free fall”?

Levermann: When we cross a tipping point, the system transitions into a different state. Some might think the system tips immediately. But the tipping happens over decades. This free fall is then irreversible and determines the next decades. So we need to investigate what it means when the climate is in a state of falling.

STANDARD: You’ve been studying tipping points in the climate system for many years. Now you say that the greatest danger of these developments has been overlooked so far. What do you mean by that?

Levermann: Climate models that also describe tipping must calculate the development of the entire planet over very long time periods while simultaneously running many different scenarios. As a result, the focus was mainly on long-term developments—less on shorter-term statements about weather and its fluctuations. During the tipping, the climate begins to stagger, and there are enormously large fluctuations. Until now, we’ve treated this as an early warning system, but we’ve hardly investigated what effects this will have on the economy and society. We also need to understand what happens after climate systems tip. The time after tipping points is our future.

STANDARD: Where do we stand currently?

Levermann: Some systems are already beyond their critical threshold or very close to it. In West Antarctica and the Greenland ice sheet, the temperature threshold has already been exceeded. Other systems, like the collapse of the Amazon rainforest or the thawing of permafrost, could follow in the coming decades. With ocean currents, we simply can’t say at the moment, but the risk is great.

STANDARD: And what awaits us?

Levermann: Between crossing a critical temperature threshold and the actual tipping of a system, decades can pass. An ice sheet doesn’t disappear overnight. But once this process has begun, it develops its own momentum. The system begins to go haywire. We still know too little about this transition phase. We will be in this intermediate phase for at least three generations. We need to understand what will happen to the weather during the time we’re falling over the cliff. Some processes will unfold over millennia, but the unpredictable weather extremes associated with them—and especially fluctuations—have immediate effects and can be an enormous problem for the economy.

Based on research findings from PIK: the UN’s science brief on Earth system tipping points. Source

STANDARD: Given this volatility, do we simply need to learn to live with the uncertainty?

Levermann: On one hand, yes. On the other hand, we must prevent it from getting worse. When we burn fossil fuels today, we’re putting carbon into the atmosphere that was locked away for millions of years—we need to be clear about that. We’ve already caused 1.5 degrees of global warming. The temperature will continue to rise as long as we burn coal, oil, and gas. We must bring CO_₂ emissions to zero. That means we need structural change.

STANDARD: You work in policy advising and were a co-author of the World Climate Reports (IPCC). Is climate change still underestimated politically?

Levermann: At the moment, we’re experiencing a phase in which climate policy is being pushed back in many places. We’re seeing this in Europe and especially strongly in the United States. At the same time, the risks are growing. I believe many people still see climate protection as a kind of idealistic environmental project. But now dependencies in energy supply are becoming apparent—if the Strait of Hormuz is closed, if we’re in conflict with Russia. We also know that nuclear power is very unsafe—in France, for example, nuclear power plants have to be shut down every summer because the rivers no longer provide enough cooling water.

On the other hand, we’ve come a long way: a few years ago, renewable energies were still more expensive than fossil fuels. That reversed three years ago. By now, climate protection is also about supply security, competitiveness, and geopolitical independence.

STANDARD: In your book The Folding of the World, you describe a way to combine prosperity with adherence to planetary boundaries. How does this approach work?

Levermann: If you set a hard boundary for a system that wants to move forward—like our society or economy—for example, no longer emitting CO_₂—then it finds new solutions to move forward. The state shouldn’t prescribe every step, because that would slow down innovation. It’s about combining freedom with hard-set boundaries. That’s how democracy works: we limit things we don’t want. Within these boundaries, there’s great freedom for innovation and creativity. However, in the past, the concept of technology neutrality was misused to do nothing. That doesn’t work. The boundaries must be hard, or there will be no progress.

STANDARD: Today, Friday, it became known that the EU wants to significantly slow down CO_₂ reduction as part of the EU Emissions Trading System. How much does this brake the exit from fossil fuels?

Levermann: It’s good that the emissions trading system is preserved in its core, but at the same time it’s being slowed down. It’s important to understand that it’s a help for the economy in undergoing structural change toward a sustainable production method. It makes little economic sense to slow down this process. We’re simply arriving at the future more slowly. Do we really want that?

STANDARD: Even if Europe achieves its goals—many tipping processes unfold over decades or centuries. Can their consequences even be limited?

Levermann: If we’re successful, we can limit global warming to less than two degrees. That’s basically unavoidable. Of course, we should have acted earlier. But that doesn’t mean we can’t do anything now. Every tenth of a degree less means fewer risks.

STANDARD: Last year, a much-discussed Nature study on the economic consequences of climate change, which you were involved in, was withdrawn and had to be methodologically revised, which sparked a lot of criticism. Do such debates damage climate research?

Levermann: It was a methodological error, and that’s frustrating. But it changes nothing about the substance. In the meantime, several new studies have been published—including from Stanford and Harvard—that reach very similar results.

STANDARD: So we’ll have to accept major economic losses if we don’t act now?

Levermann: If Europe imports fossil fuels, that money flows to Russia, Iran, Saudi Arabia. Those are costs for us and our economy. If, on the other hand, we build wind farms in Europe, install solar energy systems, and modernize power grids, we’re investing in our own infrastructure, and the money stays in our economy. That’s a fundamental difference. In my view, far too little is being said about this. Often only the costs of climate protection are discussed, not the costs of inaction or the economic opportunities of transformation.

Related

Planetary Boundaries, Tipping Elements & Global Commons https://www.pik-potsdam.de/en/topics/planetary-boundaries-tipping-elements-global-commons