50 years of data reveals true extent of climate change impacts on kelp forests

by the University of Victoria
June 5, 2026

New research from the University of Victoria (UVic) has found that some kelp forests around Vancouver Island were disappearing far earlier than scientists previously thought, highlighting that climate change has been altering our ecosystems long before most people were aware anything was wrong.

“Most research has focused on recent kelp forest losses resulting from well-known marine heatwaves, like the record-breaking ‘Blob’ heatwave that hit our coast a decade ago,” says Brian Timmer, a UVic PhD student, National Geographic Explorer and lead author of the study, recently published in Ecological Applications.

Researchers reconstructed historical baselines for bull kelp and associated macroalgae communities in the northern Salish Sea using maps, aerial photos, and scuba surveys from as far back as 1972. They then replicated identical surveys and photos in 2023 to directly compare kelp forest size and seaweed abundance over 50 years.

The historical records showed that there used to be massive bull kelp forests floating at the surface, covering more than 550 hectares of the northern Salish Sea near Comox and Denman Island. This increases the previous baseline of kelp forest size for this region by a factor of ten. None of those kelp forests remain today and satellite records show that most of the bull kelp loss occurred between 1972 and 1984—well before the kelp losses documented during more recent marine heatwaves.

Keep reading: https://news.uvic.ca/media-release/climate-change-impacts-on-kelp-forests/

Read the Ecological Applications paper: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/eap.70223