Jochem Marotzke, Director at the Max Planck Institute for Meteorology, spent several years conducting research in the United States. He shares his assessment of what the Trump administration's policies mean for his American colleagues, national and international climate research, the work of the Intergovernmental Panel on Climate Change (IPCC), and climate protection efforts.
Professor Marotzke, what are your colleagues in the U.S. telling you about the state of climate research since the Trump administration took office?
Jochem Marotzke, Director at the Max Planck Institute for Meteorology in Hamburg.
Jochem Marotzke, Director at the Max Planck Institute for Meteorology in Hamburg.
Jochem Marotzke, Director at the Max Planck Institute for Meteorology in Hamburg.
© David Ausserhofer
Jochem Marotzke, Director at the Max Planck Institute for Meteorology in Hamburg.
© David Ausserhofer
I've heard mixed responses. On the one hand, NASA – which also conducts extensive climate research – seems to have been spared so far. That may be because NASA is heavily involved in high-tech and space exploration, and the Trump administration doesn’t exactly approach things with precision – they use a sledgehammer rather than a scalpel. It's possible that NASA's climate research simply slipped under their radar. On the other hand, I spoke with a colleague who has been researching for 30 years at the Geophysical Fluid Dynamics Laboratory of the National Oceanic and Atmospheric Administration (NOAA) – the same institution where Nobel laureate Syukuro Manabe worked and where the first global climate model was developed. NOAA has long been a prime target for Republicans because it explicitly represents climate science. I mentioned to this colleague that we’re hosting a symposium in September to mark our institute’s 50th anniversary. His response? He wasn’t sure if he'd still have a job by then. He sounded deeply frustrated and demoralised.
The same colleague has now asked me to use his personal email address for communication because his government email is no longer secure. The implication was clear: ‘Who knows who's spying on me?’ I've only encountered such concerns before in exchanges with Russian colleagues. But now, even in the United States – the world’s oldest democracy – we have to ask ourselves: is it safe to send this to a government email address? That’s both shocking and deeply unsettling. Back in the 1990s, the Republican Party was still very supportive of science. Now, I’m at a total loss for words at how dramatically the rejection of knowledge, hostility toward science – and censorship – have escalated.
According to media reports, despite court interventions, around 1,300 NOAA employees – roughly 10 per cent of the workforce – have been dismissed. What does this mean for hurricane warnings, which also fall under NOAA’s responsibility?
That remains unclear. But one thing that has already shocked me is this: a hurricane is such an immediate and tangible threat – there should be no ideological debate about it. U.S. political scientist Roger Pielke, who has written about the intersection of climate research and politics, distinguishes between 'tornado politics' and 'abortion politics' in this context. 'Tornado politics' are non-ideological – everyone agrees on the scientific facts. In contrast, 'abortion politics' isn’t about knowledge at all; it’s entirely about values. But even the National Hurricane Center cannot escape the culture wars. During last year’s election campaign, the Trump camp claimed that Democrats had engineered a hurricane and directed it toward Republican-governed states. And Trump himself once altered an official hurricane forecast. That’s like Alice Weidel declaring that the German meteorological service’s predictions are wrong and that the storm will actually take a different path. It’s completely absurd.
One would think that when it comes to something as crucial as hurricane warnings, the top priority would be obtaining the most accurate predictions, with everything else taking a back seat. Yet even the survival instinct fails to override ideology. Of course, the Trump administration’s recklessness is evident elsewhere – take the absurdity of firing nuclear weapons inspectors, only to later realise, ‘Oh wait, we need those experts after all,’ at which point their email addresses were no longer in service.
How do the Trump administration's attacks impact global climate research?
The first thing that comes to mind is the Argo programme, which is vital for climate research. It was initiated by two U.S. scientists and is more than 50 per cent funded by the U.S. – through NOAA. The programme consists of 4,200 buoys drifting across the oceans, measuring ocean heat content. Alongside surface temperature, precipitation, and sea level, this is one of the most critical indicators in the climate system, as over 90 per cent of the excess heat trapped by greenhouse gases is absorbed by the oceans. If NOAA is gutted, Argo is in serious danger, as the buoys need to be replaced every five years, with around 800 new ones deployed each year. From an economic standpoint, one could question why the U.S. should bear more than 50 per cent of the costs. But this is an example of how resolutely the U.S. has long assumed the leading role in climate research and how admirably much has been invested in it. That’s why so many of us in climate science have gone to the U.S. to conduct research.
Would the end of Argo affect your own research on the Atlantic Meridional Overturning Circulation (AMOC)?
No, because Argo data cannot measure the AMOC, which requires stationary measurements with high vertical resolution. Argo measures heat content, not ocean circulation. Our institute doesn’t have any projects that directly rely on Argo data. In fact, none of our projects depend on data from the U.S. However, we would still be indirectly affected if large-scale measurement programmes like Argo were to be discontinued. As someone put it so well: basic research is a network. And if the U.S. contribution to Argo were to end, it would leave a major gap in this network. But this would be a gradual process – it wouldn't be immediately noticeable if the buoys weren't replaced. Eventually, though, climate science as a whole would feel the impact if no countermeasures were taken. If the U.S. withdraws, other countries will need to step up and invest more.
Are private universities and research institutions also affected by the cuts?
Federal funding doesn’t just support agencies like NOAA. When I was a professor at MIT – also a private university – there was some baseline funding, but most of my project funding came from the National Science Foundation (NSF). The NSF operates similarly to the German Research Foundation DFG: highly competitive but relatively unbureaucratic – a fantastic organisation. We have heard that NSF funding is set to be cut by 50 per cent. That would be devastating.
What do these cutbacks mean for the IPCC’s work?
What’s happening right now is a disaster for the IPCC’s 7th Assessment Report, which is currently in preparation. NASA's chief scientist, Katherine Calvin, is leading Working Group III, which focuses on climate change mitigation. However, she has been barred from travelling, which makes it impossible for her to fulfil this role. Other contributors still have permission to travel, but they rely on federal funding to do so. If that funding is cut, many U.S. colleagues may be unable to contribute to the IPCC report. Equally concerning is the U.S. government’s decision to withdraw funding for the IPCC’s Technical Support Unit – about $3 million. This support is the backbone of every report. Without it, nothing functions. As it stands, how Working Group III will prepare its report is completely uncertain. This also shows: the Trump administration no longer honours any commitments. Even the first Trump administration at least adhered to the principle of honouring existing treaties. I think you would have to look pretty far back in history to find a Western government that no longer feels bound by anything. Similarly, Musk and his henchmen operate with a mentality reminiscent of a mafia-style operation, acting without concern for whether they are actually allowed to do what they’re doing.
It's not just climate research that's struggling in the U.S.– climate protection is in trouble, too. This issue extends to Germany and Europe as well. What's your take on the situation there?
I remember a statement by Ottmar Edenhofer, director of the Potsdam Institute for Climate Impact Research, when Trump was first elected. He said that international climate policy could withstand four years of Trump, but if he were to be re-elected, the long-term damage could be far greater. An eight-year Trump presidency, he warned, could leave lasting consequences. That seems to hold true now, even with the four-year gap between his terms. The signs weren’t promising even before Trump’s return, as we’ve seen not only in Germany but globally.
For instance, in 2024, we saw a major shift in financial markets – investment in fossil fuels increased again. Previously, there had been a divestment trend, with capital moving from fossil fuels to renewables. But this has now reversed. Of course, renewables are also being expanded, but that alone is not enough – fossil fuels must also be actively phased out. I’m sure that if the U.S. doesn’t move away from fossil fuels, it will have global repercussions. That’s a bit of speculation, but I think those who are committed to phasing out fossil fuels will continue to do so – perhaps even with a certain attitude of now more than ever. But those who had doubts before will likely feel vindicated by Trump. They’ll argue, ‘Why should we make an effort and accept disadvantages? We can’t afford it.’ Some may even claim that climate protection was nonsense from the start. There is a lot of subtle, or even open, admiration for Trump. And we are already seeing clear tendencies to gut the European Green Deal, for example. My pessimistic assessment is that the anti-free-rider argument – ‘The Americans aren’t doing it, so we shouldn’t do it either’ – will prevail.
What role can other countries such as China play in global climate protection?
China may well take on a pioneering role in climate protection – not out of genuine concern for the environment, but because its primary strategic goal is global leadership. Climate policy could simply be a convenient tool to advance that ambition. However, we must seriously consider the implications of becoming overly dependent on China. This presents a classic social dilemma.