Climate change can affect the distribution and abundance of marine life, with consequences for food for a large number of people on the Earth.
A new study published in the current issue of Proceedings of National Academy of Sciences of United States of America, says that for every degree Celsius that the world’s oceans warm, the total mass of sea animals is projected to drop by 5%.
Does not include the effects of fishing
According to the comprehensive computer-based study by an international team of marine biologists, the global marine animal biomass will decline under all emission scenarios, driven by increasing temperature and decreasing primary production. This, however, does not include the effects of fishing.
Notably, climate-change impacts are amplified at higher food web levels compared with phytoplankton. The projections made by the study provide the most comprehensive outlook on potential climate-driven ecological changes in the global ocean to date and can help adaptive management and conservation of marine resources under climate change.
University of British Columbia marine ecologist and co-author of the study said, “There are already changes that have been observed. We will see a large decrease in the biomass of the oceans, if the world doesn’t slow climate change.”
Climate change produces oceans that are acidic
While warmer water is the biggest factor, climate change also produces oceans that are more acidic and have less oxygen, which also harms sea life according to the research.
“The potential ramifications of these predicted losses are huge, not just for ocean diversity, but because people around the world rely on ocean resources,” University of Victoria biology Professor Julia Baum said.
Professor Baum, who was not part of the study said, “It makes sense. Climate change has the potential to cause serious new conflicts over ocean resource use and global food security, particularly as human population continues to grow this century.”
Study based on six global marine ecosystem models
To address the single-model limitations, the study has presented standardised ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing.
The study authors have derived average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% under low emissions and 17% under high emissions by 2100, with an average 5% decline for every 1 °C of warming.
Biggest animals are going to be hit the hardest
United Nations World Conservation Monitoring Centre in England marine ecologist and co-author of the study Derek Tittensor said, “The biggest animals in the oceans are going to be hit hardest.” A