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Acting against The Climate Crisis Costs Much Less than Not Acting, Says IPCC Candidate

Brazilian scientist Thelma Krug, who may become the first woman to ever chair the IPCC, highlights the need for quick measures involving all sectors of society

Cristiane Fontes

On Monday 10 April, Brazil nominated scientist Thelma Krug as its candidate to chair the IPCC (UN Intergovernmental Panel on Climate Change) from 2023 to 2028.

If she is elected, Dr Krug, who is already an IPCC vice-chair, will be the first woman and the first Latin American representative to head the panel. Elections will take place during a plenary session in July.

Dr Krug has a background in Mathematics, and has collaborated with the IPCC since 2002. She explains that, based on all that we have learnt and how climate science has evolved, there is an unequivocal link between human enterprise and global warming. However, this was not the main reason that drove her to put her name forward: rather, it was the commitment of thousands of IPCC authors, and the encouragement she received from her 10-year-old grandson, Luca.

Citing the latest IPCC report, released in late March, she highlights the need for change to involve all sectors of society. The report points out that our current actions do not match the urgency of our need to prevent further temperature rises.

"We need quick, deep, and sustained reductions in [greenhouse gas] emissions in order to limit global warming to 1.5 °C, or at least keep it under 2 °C", says Dr Krug, who stresses that the choices we are making now will have a direct impact on the sustainability of our future.

"The cost of action will be far less than the cost of inaction when the entire planet starts suffering from climate impacts caused by higher temperatures."

In view of the increased volume and speed of scientific production on climate change, she advocates that the IPCC should produce shorter and more frequent reports. She adds that, during its next cycle, the IPCC will also produce a special paper on cities.

"Cities contribute to approximately 90 per cent of all emissions if we consider their entire scope", she explains, building on her 37 years of experience at INPE (National Institute for Space Research), where she worked until 2019.

Dr Krug decided to resign from INPE when then-president Jair Bolsonaro (PL) accused the institute of manipulating deforestation data.

Thelma sorri ao lado de um painel de plantas verdes
Brazilian scientist Thelma Krug - Divulgação

How do you feel as the bearer of such serious warnings from the IPCC, and do you believe this might increase our cynicism and inaction? For a long time, IPCC reports have pointed towards this situation. More recently, the unequivocal association between human enterprise and global warming has been accepted as a fact.

Since 2018, the IPCC has been stressing the need for change in all sectors of society, but the response so far has not matched the level of alert. I wouldn't call it inaction. Rather, I would say that current action doesn't match the urgency to do something if we want to have a sustainable future, as proved by science.

Five years later, what we see is that this challenge has become even greater. Today’s higher frequency of extreme events shows that the costs are already high, and will be much higher in the future.

As we have said several times, the cost of action will be far less than the cost of inaction when the entire planet starts suffering from climate impacts caused by higher temperatures.

The latest IPCC report says that we still have time to contain the worst impacts of the climate crisis, providing that large and rapid reductions in greenhouse gas emissions are achieved. How can we do that? The IPCC suggests that emissions must be cut in half by 2030. I would like to stress the 1.5 °C target, since even [an increase of] 1.5 °C is already unsustainable for many insular countries.

It's not like it's the end of the world. But if that doesn't happen, things will become increasingly difficult.

The IPCC report is by no means fatalistic. The section on mitigation states that some existing efforts could indeed help us to halve [our emissions] by 2030.

Could you comment on these mitigation options? You have options for every industry. In the energy sector, we talk a lot about decarbonisation. Today, we are electrifying our vehicles, which might be a questionable solution, but which could work well in many places.

If you look at solar energy prices, they used to be very high, but today they are more affordable for wider deployment. This expansion shows some progress — not only in Brazil, but in other parts of the world, too.

We also have other examples, mainly with regard to land use in agriculture, that is, linked to deforestation reductions. This is seen as one of the key ways to achieve major reductions in emissions, and Brazil is an example of this.

We also have actions related to urban planning. In the next IPCC cycle, we will issue a special report on climate change in cities. Cities contribute to approximately 90 per cent of all emissions if we consider their entire scope.

What role should the IPCC play in the coming years, in view of the existing robust scientific consensus on the climate crisis, the political inaction, and the 2025 Paris Agreement Review? The IPCC, through increasingly robust models, makes an assessment of the [scientific] literature around the world. Scientific publications on climate change have been growing at an enormous speed.

The IPCC might decide to reflect on the importance and need for shorter reports being issued more frequently, which would allow us to be always up to date.

What have you learned as vice-chair of the IPCC, and why are you running for chair now? My nomination as a candidate for IPCC chair is the prerogative of Brazil's focal point, which is our Ministry of Foreign Affairs.

Thus, Brazil’s MFA held consultations with other ministries, and my nomination was welcomed by all, and so has my contribution to the IPCC for 22 years.

During this time, we have learnt a lot: not only in terms of understanding how science evolved, but also by bringing together a group of authors who, on a voluntary basis, devote themselves to producing that science because they believe it will result in action.

Their dedication and profound desire to make a difference made me ask myself: could I also make a difference in that role [as IPCC chair]? There are some very good candidates, and I'm one of them.

A recent analysis by the Carbon Brief portal revealed that the number of women and authors from the Global South in the IPCC has increased in recent decades, but there is still much to be done in terms of diversity. How has the IPCC been implementing its 2020 Gender Equality Policy, and what are your proposals in this regard? When we talk about gender, I think it is a little more complex. We usually consider a binary female-male approach, but today there is a much greater diversity to be taken into account.

I personally think that it is not about increasing the number of women, or increasing diversity. I think the biggest issue is whether the people who are there now — in greater numbers — are being respected. Are they being included as such, and do they have a sense of belonging?

The IPCC has commissioned a survey including everyone that worked or engaged with them from 2015 to 2023. The goal is to try to understand if they felt part of this group of authors in an equitable way, and if opportunities were offered to all those involved. I believe the findings of this study will be very important to understand our need for future action.

In a recent interview with Agência Pública, you said that Brazilian agriculture's vulnerability to climate change deserves special attention. What should be done in the coming years? This statement was based on projections made for Brazil's Midwest region, which is already suffering the impacts of climate change. In other words, with the current rate of warming, that region is already being affected; if we have a 1.5 °C temperature rise, risks will be higher due to increased droughts.

Our action plans are expected to anticipate what the future might be like. By doing so, these plans wouldn’t be saying that there is no solution; rather, they could help us prepare for the future. Embrapa has actually been developing species that are more resilient to heat and water shortage.

What should Brazil prioritize to regain credibility in the international climate stage? And what should be negotiated in terms of cooperation and funding, in addition to resources for the Amazon Fund? Our major bottleneck continues to be deforestation, which was one of the reasons why Brazil has lost much of its credibility.

I believe the Amazon Fund is not enough. It has been very important, but financially it is insufficient. This fund compensates, so to speak, for emission reductions when these are demonstrated, but we are not yet at a stage where this is sustainable.

Despite the importance of the fund, we need more investment from other countries, which will enable cooperation without initial ties, and give Brazil the conditions to start this reversal process.


Thelma Krug, 72

Dr Krug has a first degree in Mathematics from Roosevelt University (USA), and a doctoral degree in Spatial Statistics from the University of Sheffield (England). She worked as a researcher at INPE (Brazil's National Institute for Space Research) for 37 years. She was also deputy head of the National Secretariat of the Ministry of Science, Technology and Innovation, and director for Deforestation Policy at the Ministry of the Environment. At the IPCC, she co-chaired the Task Force on National Greenhouse Gas Inventories from 2002 to 2015. Since 2015, she has been one of the IPCC's three vice-chairs.


Planeta em Transe (Entranced Planet) is a series of reports and interviews with new players and experts on climate change in Brazil and around the world. This special coverage will also focus on the responses to the climate crisis during the 2022 general elections in Brazil and at COP27 (UN Climate Conference that took place in Egypt in November 2022). This project is supported by the Open Society Foundations.