IPCC Special Report Calls for Action Against Climate Change
30 September 2019
Building resilience for a sustainable future by adapting to changing lifestyles can no longer be avoided. Immediate action to limit global warming to the lowest possible level and urgently reducing greenhouse gas emissions – in line with the goal that governments set themselves in the 2015 Paris Agreement – can bring down the scale of ocean and cryosphere changes thereby preserving the ecosystems and the livelihoods that depend on them.
The Intergovernmental Panel on Climate Change (IPCC) – the UN body for assessing the science related to climate change – recently released a Special Report that further highlights the urgency of prioritizing timely, ambitious and coordinated action to address unprecedented and enduring changes in the ocean and cryosphere, i.e., the frozen components of the Earth system, including snow, glaciers, icebergs and permafrost.
This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), approved on 24 September 2019 by the 195 IPCC member governments, underscores the imperatives and the benefits of ambitious and effective adaptation for sustainable development and risks of delayed action. The IPCC Special Report is a key scientific input for world leaders gathering in forthcoming climate and environment negotiations, such as the UN Framework Convention on Climate Change Conference (COP25) in Chile in December 2019.
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. It provides the knowledge that facilitates key decisions by the various nations.
Knowledge for Urgent Action
The report finds that strongly reducing greenhouse gas emissions, protecting and restoring ecosystems, and carefully managing the use of natural resources would make it possible to preserve the ocean and cryosphere.
Here are 5 things we can learn about our endangered planet from the findings of the report:
1. Major Changes in High Mountains Affecting Downstream Communities
- People in mountain regions are increasingly exposed to hazards and changes in water availability, the report said.
- Glaciers, snow, ice and permafrost are declining and will continue to do so. This is projected to increase hazards for people, for example through landslides, avalanches, rockfalls and floods.
- Smaller glaciers found for example in Europe, eastern Africa, the tropical Andes and Indonesia are projected to lose more than 80% of their current ice mass by 2100 under high emission scenarios.
- The retreat of the high mountain cryosphere will continue to adversely affect recreational activities, tourism, and cultural assets.
2. Melting Ice, Rising Seas
- While sea level has risen globally by around 15 cm during the 20th century, it is currently rising more than twice as fast – 3.6 mm per year – and accelerating, the report showed.
- Sea level will continue to rise for centuries. It could reach around 30-60 cm by 2100 even if greenhouse gas emissions are sharply reduced and global warming is limited to well below 2°C, but around 60-110 cm if greenhouse gas emissions continue to increase strongly.
3. More Frequent Extreme Sea Level Events
- Sea level rise will increase the frequency of extreme sea level events, which occur for example during high tides and intense storms.
- Some island nations are likely to become uninhabitable due to climate-related ocean and cryosphere change, the report said, but habitability thresholds remain extremely difficult to assess.
- Increases in tropical cyclone winds and rainfall are exacerbating extreme sea level events and coastal hazards.
Hazards will be further be intensified by an increase in the average intensity, magnitude of storm surge and precipitation rates of tropical cyclones, especially if greenhouse gas emissions remain high.
4. Changing Ocean Ecosystems
- 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, the report said. Ocean warming reduces mixing between water layers and, as a consequence, the supply of oxygen and nutrients for marine life.
- To date, the ocean has taken up more than 90% of the excess heat in the climate system. By 2100, the ocean will take up 2 to 4 times more heat than between 1970 and the present if global warming is limited to 2°C, and up to 5 to 7 times more at higher emissions.
- Marine heatwaves have doubled in frequency since 1982 and are increasing in intensity. They are projected to further increase in frequency, duration, extent and intensity. Their frequency will be 20 times higher at 2°C warming, compared to pre-industrial levels. They would occur 50 times more often if emissions continue to increase strongly.
The ocean has taken up between 20 to 30% of human-induced carbon dioxide emissions since the 1980s, causing ocean acidification. Continued carbon uptake by the ocean by 2100 will exacerbate ocean acidification.
5. Declining Arctic Sea Ice, Thawing Permafrost
- The extent of Arctic sea ice is declining in every month of the year, and it is getting thinner. If global warming is stabilized at 1.5°C above pre-industrial levels, the Arctic ocean would only be ice-free in September – the month with the least ice – once in every hundred years. For global warming of 2°C, this would occur up to one year in three.
- Permafrost ground that has been frozen for many years is warming and thawing and widespread permafrost thaw is projected to occur in the 21st century. Even if global warming is limited to well below 2°C, around 25% of the near-surface (3-4 meter depth) permafrost will thaw by 2100. If greenhouse gas emissions continue to increase strongly, there is a potential that around 70% near-surface permafrost could be lost.
- Arctic and boreal permafrost hold large amounts of organic carbon, almost twice the carbon in the atmosphere, and have the potential to significantly increase the concentration of greenhouse gases in the atmosphere if they thaw.
- Wildfires are disturbing ecosystems in most tundra and boreal as well as mountain regions.
“We will only be able to keep global warming to well below 2°C above pre-industrial levels if we effect unprecedented transitions in all aspects of society, including energy, land and ecosystems, urban and infrastructure as well as industry. The ambitious climate policies and emissions reductions required to deliver the Paris Agreement will also protect the ocean and cryosphere – and ultimately sustain all life on Earth,” said Debra Roberts of the IPCC.
“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,” Roberts said.
Additional information about SROCC is available at the IPCC website.