On 24 September 2019, IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC) was approved by the 195 IPCC member governments. The latest Intergovernmental Panel on Climate Change (IPCC) Special Report highlights the urgency of prioritizing timely, ambitious and coordinated action to address unprecedented and enduring changes in the ocean and cryosphere and reveals the benefits of ambitious and effective adaptation for sustainable development and, conversely, the escalating costs and risks of delayed action. More than 100 authors from 36 countries assessed the latest scientific literature related to the ocean and cryosphere in a changing climate for the report, referencing about 7,000 scientific publications.
The report gives evidence of the benefits of combining scientific with local and indigenous knowledge to develop suitable options to manage climate change risks and enhance resilience. This is the first IPCC report that highlights the importance of education to enhance climate change, ocean and cryosphere literacy. The ocean and the cryosphere – the frozen parts of the planet – play a critical role for life on Earth. A total of 670 million people in high mountain regions and 680 million people in low-lying coastal zones depend directly on these systems. Four million people live permanently in the Arctic region, and small island developing states are home to 65 million people.
“The world’s ocean and cryosphere have been ‘taking the heat’ from climate change for decades, and consequences for nature and humanity are sweeping and severe - said Ko Barrett, Vice-Chair of the IPCC. The rapid changes to the ocean and the frozen parts of our planet are forcing people from coastal cities to remote Arctic communities to fundamentally alter their ways of life” she added.
By understanding the causes of these changes and the resulting impacts, and by evaluating options that are available, we can strengthen our ability to adapt. The Special Report on the Ocean and Cryosphere in a Changing Climate provides the knowledge that facilitates these kinds of decisions and shows that adaptation depends on the capacity of individuals and communities and the resources available to them.
The ocean is warmer, more acidic and less productive. Melting glaciers and ice sheets are losing mass, contributing to an increasing rate of sea level rise, and coastal extreme events are becoming more severe. Urgently reducing greenhouse gas emissions limits the scale of ocean and cryosphere changes. Ecosystems and the livelihoods that depend on them can be preserved.
In recent decades the rate of sea level rise has accelerated, due to growing water inputs from ice sheets in Greenland and Antarctica, in addition to the contribution of meltwater from glaciers and the expansion of warmer sea waters” said Valérie Masson-Delmotte, Co-Chair of IPCC Working Group I.
Sea level rise will increase the frequency of extreme sea level events: indications are that with any degree of additional warming, events that occurred once per century in the past will occur every year by mid-century in many regions, increasing risks for many low-lying coastal cities and small islands. Without major investments in adaptation, they would be exposed to escalating flood risks and hazards will be further be intensified by an increase in the average intensity, magnitude of storm surge and precipitation rates of tropical cyclones.
To date, the ocean has taken up more than 90% of the excess heat in the climate system and between 20 to 30% of human-induced carbon dioxide emissions since the 1980s, causing ocean acidification. Warming and changes in ocean chemistry are already disrupting species throughout the ocean food web, with impacts on marine ecosystems and people that depend on them. Ocean warming reduces mixing between water layers and, as a consequence, the supply of oxygen and nutrients for marine life. Ocean warming and acidification, loss of oxygen and changes in nutrient supplies, are already affecting the distribution and abundance of marine life in coastal areas, in the open ocean and at the sea floor. Accordingly, shifts in the distribution of fish populations have reduced the global catch potential.
“Cutting greenhouse gas emissions will limit impacts on ocean ecosystems that provide us with food, support our health and shape our cultures - said Hans-Otto Pörtner, Co-Chair of IPCC Working Group II. “Reducing other pressures such as pollution will further help marine life deal with changes in their environment, while enabling a more resilient ocean.”
“The more decisively and the earlier we act - said Debra Roberts, Co-Chair of IPCC Working Group II, 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”.