“Blue Carbon” to mitigate climate change
Carlos Duarte, who spent part of his career in Spain – at the Institute of Marine Sciences in Barcelona, the Blanes Centre of Advanced Studies, and the Mediterranean Institute for Advanced Studies in Mallorca (all CSIC) – expressed his satisfaction yesterday at joining the list of awardees in this category, which he described as “practically a genealogy of worldwide research in ecology.”
His longstanding interest in the impact of environmental change on marine ecosystems led him to the discovery, reported in a seminal 1996 paper, that seagrass meadows, mangroves, macroalgae, and salt-marshes are heavily vegetated coastal ecosystems that, through photosynthesis, absorb large quantities of atmospheric CO2 and bury it in seabed sediments.
These ecosystems, which Duarte has termed “the hidden forests of the biosphere” accordingly act as powerful carbon sinks. “For the first time,” he explains, “we were able to calculate that, globally, these ecosystems produce major carbon surpluses, and these surpluses have to find their way into sediments.”
A decade later, his research would produce the first global estimate of the effectiveness of these sinks based on real rather than inferred data, leading to the conclusion that “despite accounting for just 0.2% of the ocean’s surface, they are responsible for 50% of the burial of carbon in marine sediments.”
It was this finding that led Duarte to coin the term Blue Carbon in 2005, in reference to these ecosystems. The United Nations invited him to lead a report into the utility of vegetated coastal habitats as a possible solution to climate change, a strategy that has since won the attention not just of scientists but also of political leaders and conservation managers.
“When people talk about nature-based solutions to climate change, they are talking about blue carbon,” Duarte insists, adding that “I have been contacted by lots of countries interested in estimating their blue carbon resources, so they can mitigate climate change with mangroves and seagrasses.”
The reef sentinel
Terence Hughes is a world authority in the study of coral reef ecology and the damage being done to it by climate change and other threats like pollution and overfishing. By the mid-1990s, various papers of his authorship in high-impact journals had alerted the world to the degraded state of reefs in all quarters of the globe.
“Coral reefs,” he explained yesterday after hearing of the award, “are not just beautiful places where wealthy people can enjoy a holiday. We should not forget that 400 million people depend on them for their livelihoods and their food security.”
Hughes’ research has focused on the coral bleaching caused by climate change. Bleaching occurs when reefs are exposed to stressors such as warming ocean waters and, if it is severe and prolonged enough, many of the corals will die. It will then take at least a decade to replace them.
Studies he led have shown that mass coral bleaching was unknown until the 1980s, but that since then repeated bleaching episodes at the regional scale and large-scale coral death have become something of a norm as temperatures continue their advance.
There is no doubt that Australia’s Great Barrier Reef, the planet’s largest, is in a critical state due to rising temperatures. In fact, it has suffered four bleaching events since 1998, two in the consecutive years of 2016 and 2017, causing damage on an unmatched scale. Last year, a paper by Hughes appearing in Nature showed that coral larvae births on the Great Barrier Reef slumped by 89% in 2019 with respect to the historical average due to the unprecedented dying-off of adult corals after the temperatures spikes of 2016 and 2017.
“Although overfishing and pollution also cause deterioration, the greatest threat facing reefs today is without doubt climate change,” affirms Hughes. “And this is not a risk that might affect them in future, but something that is harming them right now.”
While it is obviously vital to understand the relationship between climate change and coral reef degradation, Hughes believes that part of the challenge is a “crisis of governance” involving factors to do with politics, the economy, and, definitively, “how society conducts its decision-making.” For this reason, he works alongside economists, political scientists, and other researchers in the social sciences to develop strategies to combat the reef deterioration being driven by climate change.
“It is still not too late. The window of opportunity to save reefs remains open, but it is closing rapidly, so we have to act now to reduce pollutant emissions and stop wasting time.”
The largest fish database
Among Daniel Pauly’s signal achievements is the creation, in 1990, of the world’s largest online fish database, FishBase; an ecological resource setting out information on some 34,000 species that is consulted and cited by researchers around the globe. Not only that, Pauly has led the introduction of new data-gathering methods on worldwide fisheries, and developed equations and models to assess the fishing stress suffered by a given population and draw up reliable estimates.
His work, reported in numerous papers in top scientific journals, has shown that fisheries are the major driver of change in the marine ecosystem. “They are the most important factor, more than pollution, although this may change in the future with global warming,” said the new laureate yesterday after hearing of the award.
Other contributions singled out by the committee are his development of a powerful computer-based method to estimate the population dynamics of fishes and “a demonstration of climate-change-induced fish migrations.” One conclusion of this work is that fishes are moving around five kilometers closer to the poles each year.
For Pauly, “the degradation of marine ecosystems is extremely serious, we are losing the ability of the oceans to supply us with food.” However, he too is confident that humanity can save the situation if we make the decision to act.
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