際際滷

際際滷Share a Scribd company logo

The Ocean and Cryosphere in a Changing Climate

Intergovernmental Panel on Climate Change
Intergovernmental Panel on Climate Change

Symposium on Sea Level Rise in Southeast Asia 23 October 2019, Singapore Ko Barrett and Gregory Flato

1 of 18
Downloaded 66 times
The Ocean and Cryosphere in a Changing Climate #SROCC Symposium on Sea Level Rise in Southeast Asia 23 October 2019, Singapore Ko Barrett and Gregory Flato
The worlds ocean and cryosphere have been taking the heat from climate change for decades. Consequences for nature and humanity are sweeping and severe.
High Mountains Polar Regions Ocean and Marine LifePhoto: Mr. JK Ocean & Marine Life Sea Level Rise
Photo: Glenn R. Specht Sea Level Rise
Greenland and Antarctic ice sheets are melting, and are now the major cause of accelerating global sea level rise, outpacing sea level rise caused by ocean thermal expansion. During the 20th century, the global mean sea level rose by about 15cm. Sea level is currently rising more than twice as fast and continuing to accelerate. Marine heatwaves have doubled in frequency since the 1980s and have become longer-lasting, more intense and more extensive, especially harming warm-water corals, kelp forests and the distribution of marine life. Key findings relevant to Sea Level Rise
Sea level changes for several reasons IPCC SYR 2001
We can observe and model these changes Ocean warming Melting mountain glaciers Greenland/Antarctica ice sheet loss IPCC WG-I 2013
Global mean sea-level rise, over the period 19022015, is 0.16 m (likely range 0.120.21 m). The rate of rise is unprecedented over the last century (high confidence). The sum of ice sheet and glacier contributions over the period 20062015 is the dominant source of sea-level rise, exceeding the thermal effect. The dominant cause of global mean sea level rise since 1970 is anthropogenic (human) forcing (high confidence). Historical values
Sea-level rise has accelerated (extremely likely) due to increased ice loss from the Greenland and Antarctic ice sheets (very high confidence). Mass loss from the Antarctic ice sheet over the period 2007 2016 tripled relative to 19972006. For Greenland, mass loss doubled over the same period (likely, medium confidence). Acceleration of ice flow and retreat in Antarctica, which has the potential to lead to sea-level rise of several metres within a few centuries, is observed in some locations of Antarctica (very high confidence). Current Status
Sea-level rise is not globally uniform and varies regionally. Regional differences, within 賊30% of the global mean sea-level rise, result from land ice loss and variations in ocean warming and circulation. 19011920 to 19962015 (Based on climate model simulations)
Future Projections (based on high and low emission scenarios)
Year at which event becomes annual Due to projected global mean sea-level rise, local sea-levels that historically occured once per century are projected to become at least annual events at most locations during the 21st century Sea level extremes
Various adaptation approaches are already being implemented, including: o protection o accommodation o ecosystem-based adaptation o coastal advance o managed relocation People with the highest exposure and vulnerability are often those with the lowest capacity to respond. Response options
Although ongoing sea-level rise is inevitable, ambitious mitigation will have a profound effect on the rate and ultimate magnitude of sea-level rise. In the longer term, choices matter
Knowledge for action The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate highlights the urgency of prioritizing timely, ambitious and coordinated action to address widespread and enduring changes in the ocean and cryosphere; empowers people, communities and governments to tackle the unprecedented transitions in all aspects of society; provides evidence of the benefits of combining scientific with local and indigenous knowledge.
The more decisively and 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.
Our ocean and cryosphere They sustain us. They are under pressure. Their changes affect all our lives. The time for action is now.
More Information: Website: http://ipcc.ch IPCC Secretariat: ipcc-sec@wmo.int IPCC Press Office: ipcc-media@wmo.int @IPCC_CH @IPCCNews @IPCC_Climate_Change www.vimeo.com/ipcc www.youtube.com/c/ipccgeneva Find us on:

More Related Content

The Ocean and Cryosphere in a Changing Climate

  • 1. The Ocean and Cryosphere in a Changing Climate #SROCC Symposium on Sea Level Rise in Southeast Asia 23 October 2019, Singapore Ko Barrett and Gregory Flato
  • 2. The worlds ocean and cryosphere have been taking the heat from climate change for decades. Consequences for nature and humanity are sweeping and severe.
  • 3. High Mountains Polar Regions Ocean and Marine LifePhoto: Mr. JK Ocean & Marine Life Sea Level Rise
  • 4. Photo: Glenn R. Specht Sea Level Rise
  • 5. Greenland and Antarctic ice sheets are melting, and are now the major cause of accelerating global sea level rise, outpacing sea level rise caused by ocean thermal expansion. During the 20th century, the global mean sea level rose by about 15cm. Sea level is currently rising more than twice as fast and continuing to accelerate. Marine heatwaves have doubled in frequency since the 1980s and have become longer-lasting, more intense and more extensive, especially harming warm-water corals, kelp forests and the distribution of marine life. Key findings relevant to Sea Level Rise
  • 6. Sea level changes for several reasons IPCC SYR 2001
  • 7. We can observe and model these changes Ocean warming Melting mountain glaciers Greenland/Antarctica ice sheet loss IPCC WG-I 2013
  • 8. Global mean sea-level rise, over the period 19022015, is 0.16 m (likely range 0.120.21 m). The rate of rise is unprecedented over the last century (high confidence). The sum of ice sheet and glacier contributions over the period 20062015 is the dominant source of sea-level rise, exceeding the thermal effect. The dominant cause of global mean sea level rise since 1970 is anthropogenic (human) forcing (high confidence). Historical values
  • 9. Sea-level rise has accelerated (extremely likely) due to increased ice loss from the Greenland and Antarctic ice sheets (very high confidence). Mass loss from the Antarctic ice sheet over the period 2007 2016 tripled relative to 19972006. For Greenland, mass loss doubled over the same period (likely, medium confidence). Acceleration of ice flow and retreat in Antarctica, which has the potential to lead to sea-level rise of several metres within a few centuries, is observed in some locations of Antarctica (very high confidence). Current Status
  • 10. Sea-level rise is not globally uniform and varies regionally. Regional differences, within 賊30% of the global mean sea-level rise, result from land ice loss and variations in ocean warming and circulation. 19011920 to 19962015 (Based on climate model simulations)
  • 11. Future Projections (based on high and low emission scenarios)
  • 12. Year at which event becomes annual Due to projected global mean sea-level rise, local sea-levels that historically occured once per century are projected to become at least annual events at most locations during the 21st century Sea level extremes
  • 13. Various adaptation approaches are already being implemented, including: o protection o accommodation o ecosystem-based adaptation o coastal advance o managed relocation People with the highest exposure and vulnerability are often those with the lowest capacity to respond. Response options
  • 14. Although ongoing sea-level rise is inevitable, ambitious mitigation will have a profound effect on the rate and ultimate magnitude of sea-level rise. In the longer term, choices matter
  • 15. Knowledge for action The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate highlights the urgency of prioritizing timely, ambitious and coordinated action to address widespread and enduring changes in the ocean and cryosphere; empowers people, communities and governments to tackle the unprecedented transitions in all aspects of society; provides evidence of the benefits of combining scientific with local and indigenous knowledge.
  • 16. The more decisively and 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.
  • 17. Our ocean and cryosphere They sustain us. They are under pressure. Their changes affect all our lives. The time for action is now.
  • 18. More Information: Website: http://ipcc.ch IPCC Secretariat: ipcc-sec@wmo.int IPCC Press Office: ipcc-media@wmo.int @IPCC_CH @IPCCNews @IPCC_Climate_Change www.vimeo.com/ipcc www.youtube.com/c/ipccgeneva Find us on: