Fire Earth

Earth is fighting to stay alive. Mass dieoffs, triggered by anthropogenic assault and fallout of planetary defense systems offsetting the impact, could begin anytime!

Posts Tagged ‘Sea level rise’

Massive Lake of Meltwater Discovered Under Greenland Ice

Posted by feww on December 23, 2013

Researchers discover a meltwater aquifer beneath the southern Greenland ice sheet

The aquifer, representing a previously unknown storage mode for water within the ice sheet, was discovered in 2011, when researchers drilled deep beneath the ice layer and found water flowing back to the surface despite the freezing air temperatures of -15ºC.

The aquifer covers an area of about 70,000 km², an area the size of Ireland, with depth to the top of the water table of 5 to 50m.

The liquid water is held in firn—partially compacted snow—which has the “capacity to store significant amounts of meltwater in liquid or frozen form,” researchers said, “and thus delay its contribution to sea level. Here we present direct observations from ground and airborne radar, as well as ice cores, of liquid water within firn in the southern Greenland ice sheet.”

Meltwater from the Greenland ice sheet significantly contributes to the  rise in sea levels. About half of Greenland’s mass loss has been attributed to meltwater runoff.

“Surface melt has been spreading and intensifying in Greenland, with the highest ever surface area melt and runoff recorded in 2012,” say the researchers.

A Surprise Discovery

“This discovery was a surprise,” said Prof Rick Forster the lead author from the University of Utah.

“Instead of the water being stored in the air space between subsurface rock particles, the water is stored in the air space between the ice particles, like the juice in a snow cone.”

Scientists are puzzled about the speed, direction and final destination of the meltwater.

“It depends on whether it is currently connected to a system that is draining into the ocean or if it is a bit isolated and completely acting as a storage source without a current connection,” said Forster.

“We don’t know the answer to this right now. It’s massive, it’s a new system we haven’t seen before – we need to understand it more completely if we are to predict sea level rise.”

The research is published in the journal, Nature Geoscience, Published online 22 December 2013.

-0O0-

Greenland’s Surface Ice Melt

greenland melt extent 2013
An all-time record high temperature for Greenland may have been set in 2013, according to NSIDC.

greenland melt extent 2012-2013 -2
The graph above shows the daily percent of the Greenland Ice Sheet surface that has shown melt, as of August 19, 2013 (red), along with the daily surface melt extent for 2012 (blue) and the average melt extent for 1981 to 2010 (dashed line). Two peak extent days are noted.
Credit: National Snow and Ice Data Center/Thomas Mote, University of GeorgiaHigh-resolution image

-0O0-

Title: Extensive liquid meltwater storage in firn within the Greenland ice sheet
Authors: Richard R. Forster et al.
Abstract:

Mass loss from the Greenland ice sheet contributes significantly to present sea level rise. High meltwater runoff is responsible for half of Greenland’s mass loss. Surface melt has been spreading and intensifying in Greenland, with the highest ever surface area melt and runoff recorded in 2012. However, how surface melt water reaches the ocean, and how fast it does so, is poorly understood. Firn—partially compacted snow from previous years—potentially has the capacity to store significant amounts of melt water in liquid or frozen form, and thus delay its contribution to sea level. Here we present direct observations from ground and airborne radar, as well as ice cores, of liquid water within firn in the southern Greenland ice sheet. We find a substantial amount of water in this firn aquifer that persists throughout the winter, when snow accumulation and melt rates are high. This represents a previously unknown storage mode for water within the ice sheet. We estimate, using a regional climate model, aquifer area at about 70,000km2 and the depth to the top of the water table as 5–50m. The perennial firn aquifer could be important for estimates of ice sheet mass and energy budget.

Posted in Significant Event Imagery, significant events | Tagged: , , , , , , | Leave a Comment »

2012 one of 10 warmest years on record globally

Posted by feww on August 7, 2013

The following excerpts are from ‘State of the Climate in 2012,’ a 2-dimentional annual report prepared by the American Meteorological Society (AMS), with researchers from NOAA’s National Climatic Data Center in Asheville, NC acting as lead editors.

.

Earth more rapidly warming since 1970: Report

Since 1976, the earth has experienced annual temperatures above the long-term average. The rate of warming is 0.06°C (0.11°F) per decade since 1880 and a more rapid 0.16°C (0.28°F) per decade since 1970, according to the 2012 annual report from NOAA’s National Climatic Data Center.

globalsurfacetemp_1880-2012_NOAA
Earth’s average annual surface temperature is higher today than it was when record keeping began more than a century ago. The red line shows how far above or below the 1981–2010 average (dashed line at zero) the combined land and ocean temperature has been each year since 1880. The data shown are from NOAA’s National Climatic Data Center, one of several temperature analyses included in the State of the Climate in 2012, all of which show a similar warming trend. Graph adapted from Figure 2.1, in BAMS State of the Climate in 2012.

The largest of warm anomalies in 2012 were observed across the Northern Hemisphere higher latitudes: The United States,  Canada, southern Europe, western Russia and the Russian Far East, said the report.

Sea levels reached record highs in 2012. Globally, sea level has been increasing at an average rate of 3.2 ± 0.4 mm per year over the past two decades.

The global surface temperature ranked among the top 10 warmest years on record. Over land and ocean combined, 2012 was between 0.14° and 0.17° Celsius (0.25°and 0.31° Fahrenheit) above the 1981–2010 average, depending on the analysis. The globally averaged annual temperature over land was 0.24°–0.29°C (0.43°-0.52°F) above average. And averaged globally, the 2012 ocean temperature was 0.10°–0.14°C (0.18°-0.25°F) above average. [NOAA]

GlobalSurfaceTemperatureAnomaly2012
Surface temperatures in 2012 compared to the 1981-2010 average. NOAA map by Dan Pisut, NOAA Environmental Visualization Lab, based on based on Merged Land and Ocean Surface Temperature data from the National Climatic Data Center. Full report is posted HERE.

Related Links [External]

Posted in Global Temperature, global Temperature Anomalies, Significant Event Imagery, significant events | Tagged: , , , , , , | Leave a Comment »