Contemporaneous with the UN Climate Change Summit, the Intergovernmental Panel on Climate Change (IPCC) released its special report on the state of oceans and cryosphere 24 September.
The Panel highlights the urgency of prioritising ambitious and coordinated action to cope with rapid, unprecedented and long-lasting changes in the frozen components of the earth caused by climate change. The report addresses water in its “cold” status: snow, glaciers, ice sheets, icebergs and sea ice, ice on lakes and rivers in addition to permafrost and seasonally frozen ground as well as ocean “health”.
The cryosphere represents about 70% of all fresh water on Earth, where the oceans represent 96.5% of all water everywhere. Put differently, the cryosphere and ocean represent, in turn, the majority of all potable water and all water on Earth.
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.
The IPCC draws its assessments from thousands of scientific papers that are published each year. In this report, 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 indicates that there is overwhelming evidence that the additional increase in temperature of 1°C above the pre-industrial level has already resulted in profound consequences for ecosystems and people. Melting glaciers and ice sheets are causing sea level rise, and coastal extreme events are more frequent and severe.
The focus on mountains is important as mountains have been found to be warming faster than elsewhere. The rise in temperatures has caused methane emissions, the loss of ice face and a loss of the ability to reflect light. As temperatures rise, white mountain snow melts, and light that would have been naturally reflected by the ice instead is re-focused on the mountain itself. If melting ice is not replaced, more sunlight gets through and creates a warming cycle.
This accelerates the ice melt, thereby affecting billions that depend on the ice in one way or another. As mountain glaciers retreat, they are also altering water availability and quality downstream, with implications for many sectors such as agriculture and hydropower.
Millions of people that live in the Arctic region, and more than half a billion more in mountain regions, and roughly an equal number in low-lying and downstream coastal zones depend on the frozen parts of the planet for water. There are an additional estimated 65 million people that live in island states that are directly exposed to sea levels that are rising as a consequence of climate change and the development of rapid ice melt.
The report also discusses drinking water, mountain runoff, and mountain habitability and other sections deal with polar regions and sea level rise, with particular focus on coastal and low-lying areas. Some areas experience droughts from lack of rain and low snowmelt. In addition, the ocean is becoming acidified, driven by CO2 emissions, coral reefs are dying and algae blooms are more frequent and severe. Polar ice cap melt in Greenland and Antarctica could flood coastal cities and possibly submerge island nations.
Importantly, the report addresses the escalating costs and risks of delayed action and identifies the benefits of ambitious and effective adaptation for sustainable development.
Download full report here.
“The open sea, the Arctic, the Antarctic and the high mountains may seem far away to many people,” said Hoesung Lee, Chair of the IPCC. “But we depend on them and are influenced by them directly and indirectly in many ways – for weather and climate, for food and water, for energy, trade, transport, recreation and tourism, for health and wellbeing, for culture and identity.”
“If we reduce emissions sharply, consequences for people and their livelihoods will still be challenging, but potentially more manageable for those who are most vulnerable,” Lee said. “We increase our ability to build resilience and there will be more benefits for sustainable development.”