From blue whales colliding with ships to African elephants raiding crops in villages, the climate crisis is causing a rise in conflicts that lead to injury or death for humans and wildlife, new research shows.
The climate crisis is making food, water and healthy habitats harder to come by, forcing animals and human populations into new ranges or previously uninhabited places. It is also changing the way they behave. This means a rise in human-wildlife conflicts, as well as damage to personal property and loss of livelihoods for people, according to a review paper led by the University of Washington.
The team looked at 30 years of research and found that the number of studies linking climate breakdown to conflict had quadrupled in the past 10 years compared with the previous two decades. They warn of an “extraordinary breadth” of places already affected.
The paper, published in Nature Climate Change, looked at 49 cases of human-wildlife conflict on every continent except Antarctica, and in all five oceans. From 2.5mg mosquitoes to 6,000kg African elephants, conflicts involved all major wildlife groups – birds, fish, mammals, reptiles and invertebrates.
Changes in temperature and rainfall were the most common drivers of conflict, cited in more than 80% of case studies. The most common outcome was injury or mortality to people (43% of studies) and wildlife (45% of studies). Conflicts are defined as direct interactions between humans and wildlife that have a negative outcome for one or both.
“We were surprised that it’s so globally prevalent, this was one of the big takeaways of this paper,” said the lead researcher, Briana Abrahms, a wildlife biologist from the University of Washington.
“There hasn’t been as much recognition as there should be that climate change is exacerbating these conflicts,” she said. “We might see new conflicts in places they haven’t been in the past, as well as conflicts intensifying in places they have been in the past.”
Human-wildlife conflicts are already a leading cause of decline and extinctions among large mammals, which can trigger changes in ecosystems, according to the paper.
“Recognising the connection between climate change and human-wildlife conflict is essential for anticipating, and ultimately addressing, new and intensified human-wildlife interactions in the 21st century and beyond,” the researchers concluded.
They give a number of examples of where human-wildlife conflict is growing due to climate change:
• In Sumatra, forest fires after an El Niño-induced drought drove tigers and elephants into new areas, causing at least one human death.
• Animals may be increasingly nocturnal to avoid hotter temperatures during the day, which leads to more attacks on livestock when people are asleep, which can then lead to retaliatory killings.
• Across the Arctic, climate change is reducing the amount of sea ice, meaning polar bears are increasingly forced to hunt on land. The number of human-polar bear interactions tripled in the Canadian town of Churchill, Manitoba, known as the “polar bear capital of the world”, between 1970 and 2005.
• Blue whales are changing their migration timings as marine heatwaves become more frequent, increasing collisions with ships.
• Drought is forcing elephants in Tanzania to look for food and water nearer villages, causing crop damage and retaliatory killings.
• In Scotland, warming temperatures are driving an increase in barnacle geese, which eat grass farmers want for their sheep.
Photograph: Mick Durham FRPS/Alamy
“Our systematic review revealed an extraordinary breadth of systems in which climate-driven conflicts are occurring worldwide,” the researchers said. They did not look at the spread of disease transmission but this is “also a well-documented consequence of climate change”.
They also highlight the need to anticipate where conflict is likely to occur in the future, and work out ways to minimise it, such as creating early warning systems about wildlife moving into areas prone to drought or megafires.
A success story highlighted in the paper is California’s Whale Entanglement Risk Assessment and Mitigation Program (Ramp) in the north-west Pacific Ocean, which looks at real-time changes in climate, ecosystem and fisheries to work out the risk of whales getting entangled in fishing gear and acts to reduce the probability of this happening, such as temporarily closing fisheries.
