EMBRACER stands for Earth systeM feedBack ReseArch CEntRe, a consortium of Utrecht University, the Royal Netherlands Institute for Sea Research (NIOZ), Vrije Universiteit Amsterdam, Radboud University Nijmegen, and Wageningen University & Research. "In the short term, up to the middle of this century, we have a good understanding of how climate change is unfolding," says Appy Sluijs, professor of Paleoceanography at Utrecht University. "But important feedback mechanisms work slowly, and their full impact will only become visible in the coming decades to centuries. Even with rigorous climate measures, they will determine Earth's climate well beyond 2100. However, we currently lack scientific insight to anticipate their impact. With EMBRACER, we are truly taking the next step."
Bridging the gap
Within EMBRACER, 23 top Dutch researchers from a very broad palette of climate sciences work together: from earth scientists and geochemists to oceanographers, climatologists, polar researchers, hydrologists, and ecologists. Thanks to this interdisciplinary approach and the integration of research methods and timescales, EMBRACER bridges the gap between predicting short-term and long-term climate change. The need for such an approach is evident from the fact that even the best future projections still pay little attention to feedback mechanisms that are crucial over timescales of decades to millennia. "But these future projections are the basis of climate policy," warns Sluijs. "Which means we might be vastly underestimating sea level rise or warming in the second half of this century."
Thawing permafrost
Earth scientist Jorien Vonk of Vrije Universiteit Amsterdam will focus on the feedback mechanisms of warming permafrost. This frozen ground contains about twice as much carbon as is currently in the atmosphere in the form of CO2. Enhanced thawing due to global warming leads to the breakdown of this carbon and the production of CO2 or methane (CH4). "Our knowledge of the vast polar region is increasing, and fortunately, the role of permafrost in the global balance of Earth's system is increasingly being recognized and acknowledged. However, the CO2 emissions that occur due to thawing are extremely difficult to predict because local and regional variability is enormous," says Vonk. "I think with the EMBRACER climate dream team, along with the many international colleagues we work with, we can make a significant step forward and better estimate how much this feedback will impact our emission reductions."
The future of tropical forests
Within EMBRACER, the research at Wageningen University & Research (WUR) focuses on the fate of tropical forests. These are threatened by climate change and deforestation, even in the surrounding peatland areas like the Pantanal in the Amazon. Higher temperatures and longer droughts make trees vulnerable and dry out the peat soils. "We risk tropical forests becoming net emitters of CO2, exacerbating climate change, whereas they have so far done the opposite," says Wouter Peters, professor of the carbon cycle at WUR. An increase in the number of forest fires, the field of WUR professor Guido van der Werf, can also play an important role in this. Together with other researchers within the consortium, they will measure CO2 flows in the atmosphere, forests, and rivers to investigate the risk of much tropical forest disappearing and to better understand what feedbacks on our climate will ultimately arise from this.
Increased methane emissions
The contribution of biogeochemist Caroline Slomp (Radboud University Nijmegen) to EMBRACER consists of research into emissions of the greenhouse gas methane (CH4). "Globally, methane emissions from lakes and coastal waters to the atmosphere are steadily increasing. Methane is a much stronger greenhouse gas than CO2, so this is a really big problem. We know that eutrophication plays a role: fertilizers from fields often leak into surface waters and cause strong growth of various organisms. When these organisms die and rot, you often get CH4. We want to investigate under what circumstances this CH4 forms and escapes into the atmosphere. Then we can also come up with measures to limit these emissions in the future."
CO2 in the oceans
Gert-Jan Reichart, professor of marine geology affiliated with both NIOZ and Utrecht University, will focus within the project on the interaction between oceans and the atmosphere, and how this will affect CO2 uptake in the ocean in the coming period. "If we look at geological history, under normal conditions, the ocean is the all-determining factor for CO2. The atmosphere is a slave to the ocean, so to speak. But for the first time in millions of years, humans have reversed these roles: through our CO2 emissions, the atmosphere now determines what happens in the ocean. This will undoubtedly have far-reaching consequences for the natural carbon cycle and thus for the development of atmospheric CO2 in the coming period."
Ice and ocean dynamics
OceanographerAnna von der Heydt from Utrecht University investigates how the feedbacks affect ice and ocean dynamics and their interactions with the carbon cycle. The polar ice caps and the Gulf Stream are both mentioned as potential tipping elements that can undergo abrupt transitions with global consequences. Although much is still unknown about these individual systems, their thresholds, and dynamics, many of the feedbacks operate at the interface between these large-scale climate components. This means that ocean circulation and ice sheet dynamics are closely interconnected, also through their impact on the carbon cycle. Based on recent observations and climate records from the past, Von der Heydt and her colleagues aim to study and improve the next generation of climate models for long-term future projections.
The geological past as a blueprint
Sluijs' contribution to EMBRACER consists of research into climate changes in the geological past. "If feedback mechanisms are important in the future, they were also important in the past. Reconstructions of climate changes based on sediments once deposited on the seabed show this. After the last ice age, the permafrost in the Netherlands melted, and 56 million years ago, a chain reaction of feedbacks caused massive emissions of CO2 and methane. Our challenge now is to make the reconstructions so accurate that we find out why such feedback mechanisms became active, how strong they were, and what influence they had on the climate. Combined with current knowledge, this provides predictive value for the future."
SUMMIT grants
The EMBRACER project is one of five collaborations supported within NWO's prestigious SUMMIT program. The SUMMIT grant recognizes world-class collaboration, which can be further strengthened with this support. See further the press release of NWO.
