The double burden of climate change

Fishers on a shallow reef in Ahus Island, Papua New Guinea © Dean Miller

A new study on the effects of climate change in five tropical countries has found fisheries are in more trouble than agriculture, and poor people are in the most danger.

Distinguished Professor Joshua Cinner from James Cook University's ARC Centre of Excellence for Coral Reef Studies led the study. He said tropical regions are expected to suffer losses in both fisheries and agriculture as the effects of climate change increasingly make themselves felt.

"For example, by 2100 tropical areas could lose up to 200 suitable plant growing days per year due to climate change. Likewise, in some tropical areas fishable biomass in the ocean could drop by up to 40 per cent," said Professor Cinner.

"Yet assessments of climate change impacts and the policy prescriptions that come from them rarely consider changes to agriculture and fisheries simultaneously, and those that do are at the national scale.

"These larger-scale assessments gloss over how households and even entire communities will be affected by climate change."

Prof Cinner led a team of 28 researchers who investigated the potential impacts of climate change on agriculture and fisheries for 72 coastal communities across Indonesia, Madagascar, Papua New Guinea, the Philippines, and Tanzania.

The authors integrated socioeconomic surveys from over 3,000 households with model projections of losses to crop yield and fisheries catch under a high emissions scenario (SSP 5-8.5) and a low emissions scenario (SSP 1-2.6).

They found that, although different communities vary in how vulnerable they are both within and across countries, the communities with lower socioeconomic status are particularly exposed to severe impacts and have higher dependence on natural resources, so these impacts will hit harder.

"We found that the potential losses are expected to be higher in the fisheries sector than agriculture overall, but the big problem is that two thirds of the communities we studied will experience potential losses to both fisheries and agriculture simultaneously, under a high emissions scenario," said Professor Cinner.

"Our in-depth surveys revealed that many people have limited opportunity to adapt to changes by switching livelihoods between food production sectors.

"But climate change mitigation - reducing greenhouse gas emissions - could reduce the proportion of places facing that double burden by half.

"It really does show how much the lives of very many ordinary people hinge on decisions they have no control over and highlights the moral responsibilities that decision makers have towards them," said Professor Cinner.

Paper

Cinner JE, Caldwell IR, Thiault L, et al. 2022. 'Potential impacts of climate change on agriculture and fisheries production in 72 tropical coastal communities'. Nature Communications. DOI: 10.1038/s41467-022-30991-4