This month the U.N.’s Intergovernmental Panel on Climate Change (IPCC) released a Special Report on Global Warming of 1.5˚C. It details the consequences of climate change if temperatures rise 1.5˚C above pre-industrial levels, a critical threshold above which climate impacts rise rapidly. While a limit of 1.5˚C is preferable to the more practical target of 2˚C set by the Paris Agreement in 2015, even a 1.5˚C rise will have major consequences. These include examples such as higher sea levels, more extreme weather events, warmer oceans, and a drastic reduction in large ecosystems such as coral reefs. As of now, this limit of 1.5˚C is unlikely to happen without dramatic changes, including a 40-50% reduction in greenhouse gas emissions by 2030.
Given the near certainty of continued global warming to high levels, how can we protect biodiversity on both land and in the water? Keeping habitats connected will remain critical as the climate transitions to warmer temperatures.
Climate refugia are islands of habitat that will remain stable and suitable for species even as surrounding areas change. Examples include mountaintop ecosystems that remain cool due to high elevations, or areas near large lakes or oceans that are buffered by being near a large body of water. The persistence of these refugia means that individuals still have somewhere to go once their own core habitat becomes too warm. Managing climate change refugia is an important conservation option in light of current climate change.
Climate corridors will keep climate refugia connected. These linkages will act as pathways for individuals to move from their current habitat to more suitable habitat, whether that is up a mountain, across a forest, or closer to the poles. Climate corridors are distinct from climate refugia, and require new conservation strategies to remain effective. A recent map of animal migrations across North and South America shows the routes that species are likely to take as climate change forces them into new habitats.
Marine connectivity will also be affected as ocean temperatures rise along with air temperatures. The Special Report points out that the likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C, compared with at least once per decade with 2°C. Recent research has shown that climate change will alter marine connectivity inconsistently, impact the effectiveness of marine protected areas, and in some cases may alter fish migration.
As the Special Report highlights, conservation under climate change is going to remain a challenge whether or not the limit of 1.5°C is crossed. Maintaining connectivity across all landscapes will be crucial in protecting biodiversity.