AsianScientist (Jun. 5, 2021) – While environmental data forms the basis of most climate change analyses, a new Cambodia-focused study suggests that human behavior must be integrated into the climate dataset as well. Their findings were published in Science Advances.
Since 1974, the United Nations (UN) has designated June 5 as World Environment Day—with this year’s celebrations calling for urgent action to revive our damaged ecosystems, counteract climate change and prevent biological collapse. The 2021 iteration will also kick off the UN Decade on Ecosystem Restoration, a global mission to revitalize billions of hectares from forests to farmlands until 2030.
Among the many ecosystems at stake are freshwater fisheries, which mainly support around 10 percent of the population in low and middle-income countries. Due to the effects of climate change, global marine fish catch fell by four percent from 1930 to 2010, with future warming projections threatening to decrease fish harvest by another 13 percent by 2050.
Though existing models of climate effects on fisheries highlight the ecological impacts of temperature rise, few studies take human behavior into consideration.
“To accurately predict the impacts of climate change, we need to know about the effects on ecological systems, and also the effects on people who use them,” explained Assistant Professor Kathryn Fiorella from Cornell University, the study’s first author.
In the study, Fiorella and colleagues joined forces with Malaysia-based nonprofit research institution WorldFish, which collects international survey data on fisherfolk.
Tracking fisher households for two months over three years in Cambodia—which has the world’s highest per-capita consumption of inland fish—WorldFish collected information on how often people fished, how much time they spent while fishing, and what method they used.
Across a temperature range of 24 to 31 degrees Celsius, their analysis revealed that when temperatures rise, people fish less often but fish catch rates remained largely the same. Without accounting for fishers’ behavior, it would appear that temperature had no impact on fish catch.
However, the authors found that stocks of fish and other aquatic foods rose with temperatures, leading to slightly larger catches. This meant that the ecosystem was more productive during warmer periods, even with less fishers around.
According to the researchers, fishing frequencies may have declined as temperatures rose due to competing interests.
“These households have a suite of different activities they are engaged in at the same time,” Fiorella said, noting many of them are rice farmers or run small businesses.
However, unbearable heat may still be a factor. As large swaths of the population migrate to cities or nearby countries for work, these dynamics could also be pulling them away from fishing, she added.
“This study underscores the importance of pulling human behavior into climate change modeling,” concluded Fiorella. “Ultimately, understanding both ecosystem responses and people’s responses to temperature is going to be fundamental to understanding how climate change affects people who are directly reliant on the natural resources for their food and income.”
Source: Cornell University; Photo: Shutterstock.
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