Global warming has already reached 1°C above the pre-industrial level, due to past and current greenhouse gas emissions. There is overwhelming evidence that this is resulting in profound consequences for ecosystems and people. The ocean is warmer, more acidic and less productive. Melting glaciers and ice sheets are causing sea level rise, and coastal extreme events are becoming more severe. Since about 1950 many marine species across various groups have undergone shifts in geographical range and seasonal activities in response to ocean warming, sea ice change and biogeochemical changes, such as oxygen loss, to their habitats. This has resulted in shifts in species composition, abundance and biomass production of ecosystems, from the equator to the poles.
The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate, approved on 24 September 2019 by the 195 IPCC member governments, provides new evidence for the benefits of limiting global warming to the lowest possible level– in line with the goal that governments set themselves in the 2015 Paris Agreement.
Issues covered by the report include melting ice, rising seas, more frequent extreme sea level events and how ocean ecosystems are already changing. There is also evidence of the benefits of combining scientific with local and indigenous knowledge to develop suitable options to manage climate change risks and enhance resilience.
“The more decisively and the earlier we act, the more able we will be to address unavoidable changes, manage risks, improve our lives and achieve sustainability for ecosystems and people around the world – today and in the future” said Debra Roberts, Co-Chair of one of the working groups.