UBC’s William Cheung explains the latest IPCC climate change report and what it means for ocean ecosystems
William Cheung, an assistant professor at the UBC Fisheries Centre, is a lead author on the 5th Assessment report of the Intergovernmental Panel on Climate Change, which was released on March 31. His contribution focused on the health of oceans and fisheries.
What does the IPCC report say about oceans?
We know that for millions of years natural global climate change caused significant ecosystem shifts and species extinctions. This change happened at much slower rates than the human-induced climate change we are experiencing right now. Many marine species are responding to climate change by moving away from tropical waters to more temperate waters. We’ve also seen changes in their seasonal activities or migration patterns, and decreasing abundance and size. So far only a few recent species extinctions have been attributed to current climate change.
What should we take away from this report?
Climate change has impacted natural and human systems on all continents and across the oceans. Climate change is adding additional challenges to sustainable ocean management by driving changes in biodiversity, temperature, oxygen, acidification, and other water properties. This also impacts the other benefits we get from the ocean such as climate regulation.
What does this report mean for how we manage the oceans?
Climate change, which is already affecting ocean ecosystems and related sectors such as fisheries, adds to the range of challenges in sustainable ocean management. It adds to the threats of over-fishing and other stressors.
Doing our best to manage the ocean will help us reduce some level of climate change-induced risk. This includes rebuilding overfished stocks, managing fishing to a sustainable level, minimizing the impacts from pollution, protecting important habitats and conserving biodiversity. However, doing so would not eliminate all the risk, particularly in some sensitive regions. We also need to reduce greenhouse gas emission.