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Ice Generation and the Heat and Mass Transfer Phenomena of Introducing Water to a Cold Bath of Brine
Published on: March 13, 2017
Global Warming and Northern Hemisphere Sea Ice Extent
1Department of Meteorology, University of Maryland, College Park, MD 20742, USA. Department of Environmental Sciences, Rutgers-The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901-8551, USA. Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration (NOAA), Post Office Box 308, Princeton, NJ 08542, USA. Department of Atmospheric Sciences, University of Illinois, 105 South Gregory Street, Urbana, IL 61801, USA. Code 971, Oceans and Ice Branch, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA. Hadley Centre for Climate Prediction and Research, Meteorological Office, Bracknell, RG12 2SZ, UK. Climate Prediction Center, National Weather Service, National Centers for Environmental Prediction, NOAA, 5200 Auth Road, Room 800, Camp Springs, MD 20746, USA. Arctic and Antarctic Research Institute, 38 Bering Street, St. Petersburg 199397, Russia.
Northern Hemisphere sea ice extent has significantly decreased over 46 years. Climate models confirm this trend is largely due to human-caused greenhouse gas emissions, not natural variability.
Area of Science:
- Climate science
- Environmental monitoring
- Atmospheric physics
Background:
- Surface and satellite observations reveal a substantial decline in Northern Hemisphere sea ice extent over the last 46 years.
- Previous research has explored natural climate variability but has not fully reconciled observed sea ice loss with model simulations.
Purpose of the Study:
- To compare observed Northern Hemisphere sea ice trends with climate model simulations.
- To determine the likelihood of observed sea ice decline being solely due to natural climate variations.
- To project future changes in sea ice extent and thickness.
Main Methods:
- Analysis of 46 years of surface and satellite-based sea ice extent data.
- Comparison of observed trends with control and transient integrations from Geophysical Fluid Dynamics Laboratory and Hadley Centre climate models.
- Utilizing long-term climate model control runs to assess the probability of natural variability driving observed trends.
Main Results:
- Observed Northern Hemisphere sea ice extent decrease aligns with transient climate model simulations.
- Both models indicate that the observed sea ice trends are significantly larger than expected from natural climate variations alone.
- The probability of observed sea ice trends (1978-98 and 1953-98) resulting from natural variability is less than 2% and 0.1%, respectively.
Conclusions:
- The observed decrease in Northern Hemisphere sea ice extent is highly unlikely to be a result of natural climate variability.
- Climate models project continued reductions in sea ice thickness and extent throughout the next century.
- Anthropogenic factors, such as greenhouse gas emissions, are strongly implicated in the observed sea ice decline.
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