Antarctic ice melt will have the minimal impact of delaying atmospheric warming by a decade and a half but will raise sea levels rapidly and change precipitation patterns worldwide “because the tropical rain belt will shift north” according to new research published in the journal Nature. The increasing rate of meltwater will significantly alter climate projections. It is the first newly identified feedback loop in 20 years according to senior author Joellen Russell.
Ugh.
The new study came out recently, it was funded by NOAA, with data provided by the Geophysical Fluid Dynamics Laboratory, the University of Arizona led the research.
I was stunned to see that NOAA’s climate.gov web page showed up in my google search because as you know, the Trump regime has been furiously removing science from government websites since day one. It appears the source datasets were scrubbed by the fossil fuel interests that Trump embedded in those agencies tasked with protecting the environment. GFDL is an NOAA laboratory located at Princeton University. Check the dead link yourself here.
There is a second story below the fold that ties Greenland and Antarctica changes together.
x xYouTube VideoMelting is pervasive along the ice surrounding Antarctica. On the surface of the grounded ice sheet and floating ice shelves, extensive networks of lakes, streams and rivers both store and transport water. As melting increases with a warming climate, the surface hydrology of Antarctica in some regions could resemble Greenland’s present-day ablation and percolation zones. Drawing on observations of widespread surface water in Antarctica and decades of study in Greenland, we consider three modes by which meltwater could impact Antarctic mass balance: increased runoff, meltwater injection to the bed and meltwater-induced ice-shelf fracture — all of which may contribute to future ice-sheet mass loss from Antarctica.
It’s important to note that the speed up of marine ice cliff collapse we have witnessed is caused by the warming of the southern ocean due to relentless burning of fossil fuels, and not by meltwater fracture, at least not yet. It is believed that the Larsen B breakup was caused by hydrofracture.
From the University of Arizona press release.
Observations show that the Antarctic ice sheet has been melting faster in recent years.
The UA-led team found that by the year 2100, sea level could rise as much as 10 inches more than the previous estimate of approximately 30 inches by 2100.
To figure out whether the melting of the Antarctic ice sheet would affect global climate, the research team modified one of the most current climate computer models to include the ice melt.
Adding the melted ice into the team’s model indicated that the global temperature would increase by 2 degrees C (3.6 F) by the year 2065, rather than the year 2053, the team writes.
In addition to slowing warming and increasing sea level, the melting of the Antarctic ice sheet will change precipitation regimes because the tropical rain belt will shift north, said senior author Joellen Russell, who holds the Thomas R. Brown Distinguished Chair of Integrative Science and is an associate professor of geosciences at the UA.
"Our projections indicate the tropical rain belt will shift toward the Northern Hemisphere, making it slightly wetter in the Northern Hemisphere and slightly drier in the Southern Hemisphere than previously predicted," Russell said.
NOAA writes:
Ice sheet melt is a known neglected forcing in climate model simulations, contributing to uncertainties in climate projections. This is the first study to directly implement estimates of Antarctic ice sheet melt in a climate simulation, showing the actual change in climate projections due to the freshwater input. The authors used a large ensemble to confidently separate the freshwater signal from natural variability and show when we can expect these freshwater-induced effects to become significant.
The study shows that adding Antarctic ice sheet melt estimates to GFDL’s Earth System Model (ESM2M) significantly alters future climate projections. The addition of ice sheet melt to a 21st century climate projection reduces global warming. However, this comes at the more significant cost of potential increased future sea level rise through increased ocean warming. We also show that the ice sheet melt causes more precipitation just north of the equator, and less precipitation south of the equator, due to a Northwards shift in the Inter-tropical convergence zone. This means reduced future drying in areas like Central America, but increased drying in Australia. The authors propose that the freshwater input associated with the ice melt should be included in all future climate simulations to improve 21st century projections.
Observations over the satellite era show a positive trend in Southern Ocean sea ice cover. This observed trend can be simulated without ice sheet melt through natural variability, but it is far more likely to occur in climate model experiments, in a scenario with ice melt. The ice sheet melt also causes sea ice expansion until the middle of the century, suggesting that the observed trend is also likely the beginning of a longer trend.
Speaking of central America. Increased migration from these areas is linked to climate change. The president should take note.
Violence in Honduras, Guatemala, and El Salvador—three of the countries where most recent asylum seekers are coming from—is the immediate cause for people to up and leave. But as with Syria, a widespread drought that devastated farmers in Central America’s Dry Corridor has helped destabilize the region. Coffee rust—a fungus that can kill coffee plants and thrives in warmer temperatures—has affected 70 percent of Central America’s coffee farms and caused 1.7 million workers to lose their jobs.
The signs of how climate shifts are already influencing migration, coupled with a report by federal scientists warning the risks of migration and instability will only grow in a warming world would, in a rational world, lead a government to consider how to mitigate these risks. But rather than listening to the red alerts, the Trump administration has doubled down on policies that will drive carbon pollution higher. The president himself has flatly said he doesn’t believe the report.