Turn upwardly the heat, and water ice will cook. The effect of climate change on the world’s water ice is almost that elementary. Global temperatures are warming, and that warming is fastest at the poles. As a consequence, ice sheets and glaciers cook and shrink.
And then while in that location’s all the same lots of snow and ice in the polar regions, at that place’due south much less of information technology than there used to be.
Antarctica’due south Ross Water ice Shelf at the Bay of Whales.
The Trouble with Melting
Melting ice is bad news for several reasons:
Meltwater from the ice sheets and glaciers flows into the bounding main, causing sea levels to rise. This can lead to flooding, habitat destruction, and other bug.
Water ice reflects the Sun’s energy improve than than land or h2o. So with less ice, Earth absorbs more than energy, and heats upwardly faster.
Many animal species rely on icy habitats to survive—polar bears, seals, foxes, wolves, and many others are threatened past global melting.
Secrets in the Ice
Ice besides holds secrets about Earth’southward climate history. By drilling into Antarctica’due south ice sheets and extracting ancient layers, scientists can measure what the climate was similar over the last 800,000 years.
Dataset Today’s Arctic Sea Water ice Report
Today’s Arctic Body of water Water ice Report
White areas below show how much of the Arctic is currently covered by sea ice. The ice naturally grows and shrinks every winter and summertime (March has the most ice; September the least.)
Based on microwave data gathered via satellite, this prototype shows how much of the Arctic Body of water is currently covered by ice at more than xv% concentration. Source: National Snow and Ice Information Center, University of Colorado Boulder
The orange line shows the normal (median) ice coverage for that day, based on measurements from 1981–2010. Because of rise temperatures due to climate change, y’all’ll usually come across less ice than the normal line.
Chill sea ice coverage is shrinking by 3% or more per decade. And some climate models suggest that if CO2
emissions continue to rise, the Arctic Ocean could be nearly ice-gratis by 2050.
Ice levels grow and shrink in a regular bicycle each twelvemonth, but the current year’due south water ice bend on this graph is commonly well below the gray median, or normal, line for 1981–2010. See an interactive sea ice graph from the National Snow and Ice Data Center. Source: National Snow and Water ice Data Heart
Less Ice Means More than Warming
Water ice reflects sunlight; you lot know this if you’ve ever squinted against the blinding glare of sunlight on snow. (Scientists call this reflectivity
Without water ice cover, state or bounding main h2o reflects much less sunlight. And when the Sun’southward energy isn’t reflected, information technology gets captivated, causing the ocean or state to heat upwards. So the more water ice melts, the more sunlight the planet absorbs, and faster it warms.
When sunlight hits sea ice, most 90% of the light free energy gets reflected back toward the atmosphere. But ice-free ocean water reflects but 6%, and absorbs the other 94% of the energy as heat. Read more nigh albedo.
Sea Water ice versus State Water ice
In one respect, melting bounding main ice isn’t as bad as melting ice on the land. That’s considering sea water ice floats, and like melting ice cubes in a cold drinkable, it doesn’t enhance sea level when it melts.
To learn more virtually water ice, freezing and melting try the Ice Balloons Scientific discipline Snack.
More Sites about Arctic Sea Water ice
Chill Sea Ice News
Exploratorium Ice Stories: Bears of Summertime
Exploratorium Ice Stories: Arctic Seals
Dataset Today’southward Antarctic Sea Water ice Written report
Today’s Antarctic Sea Ice Report
The white area surrounding Antarctica shows how much of the sea is currently covered by bounding main ice. The ice naturally grows and shrinks every wintertime and summer (September has the almost water ice; February, the least.)
The orangish line shows the normal (median) water ice coverage for that day, based on measurements from 1981–2010.
Based on microwave data gathered via satellite, this image shows the extent of the Southern Ocean effectually Antarctica that’s currently covered by water ice at greater than fifteen% concentration. Source: National Snow and Ice Data Middle, Academy of Colorado Bedrock
The Opposite of Melting
In spite of climatic change, Antarctic sea ice has been growing past about 1.viii% per decade. Scientists aren’t sure why, but they think it may be caused by the frigid sea current that surrounds Antarctica, and by the continent’s icy winds.
Sea Water ice Growing, Land Ice Shrinking
Though Antarctic body of water water ice is growing, the ice sheets on the continent itself are shrinking—by an estimated 219 billion metric tons per year, every bit of 2018. This melting appears to exist accelerating, and is contributing to body of water level rise.
The Antarctic ice sheet has lost more than than 1,000 gigatonnes of ice since 2002, co-ordinate to ice mass measurements from NASA’s GRACE satellites.
Dataset A Frozen History of the Climate
A Frozen History of the Climate
The multicolored line in this graph shows the carbon dioxide (CO2) levels in Earth’s atmosphere, measured in water ice cadre samples from Antarctica. Information technology goes from 800,000 years ago to almost 1978.
Almost all of these CO2
measurements were taken from water ice cores nerveless in Antarctica, and published by scientists working with NOAA’south National Climate Data Heart. Source: Based on NOAA Carbon Dioxide Pumphandle video
They Call this Graph the Hockey Stick
Over hundreds of thousands of years, Globe’s COtwo
levels rose and fell, but they never got to a higher place 300 parts per one thousand thousand—until the belatedly 1800s. That’s when humans began generating COtwo
past burning more than and more than fossil fuels for energy. After 1850, the line rises so fast that it looks most vertical.
This clearly shows that CO2
levels are much college today than at any fourth dimension in the terminal 800,000 years. And direct CO2
measurements reveal that it’s still rising higher every twelvemonth.
How Does Ice Tell The states the Climate’due south History?
Antarctica’s water ice sheets formed very slowly over thousands of years, as each year’southward snowfall became compacted into solid layers of ice. When each new water ice layer formed, information technology trapped tiny bubbling of air—similar bottled samples of the atmosphere from that time. By drilling downwardly into these water ice sheets, scientists tin can measure the gases that were in World’s atmosphere many centuries ago.
As Antarctic snow builds up over many years, the layers underneath become harder and more than dense.
Credit: Oregon State University
The bubbling in this ice from an Antarctic ice core incorporate carbon dioxide and other gases, trapped thousands of years ago when the ice formed. Researchers carefully crush the water ice and capture the gases that escape to measure the CO2
Prove of Ice Ages
While past CO2
levels don’t tell us how warm the climate was, other trapped gases can. Information from oxygen and other gases testify that water ice ages happen when COtwo
levels are low, warmer periods happen when COtwo
levels are high.
Scientists measured the relative amounts of different oxygen and hydrogen isotopes in the ice core samples; these isotopes vary with temperature. These two graphs prove that loftier temperatures happened when there was more oestrus-trapping CO2
in the atmosphere. Source: Based on graph from Wikimedia Commons, original data from Petit, et al, 1999
More Sites about Ice Core Data
Exploratorium Ice Stories: Frozen History
Ice Core Data from Lawrence Berkeley Lab
Scientific American Article on Connections Betwixt CO2
Dataset As Glaciers Cook, Sea Levels Rise
Equally Glaciers Cook, Sea Levels Rise
The xanthous line rising from left to right shows the total sea level rising caused by melting glaciers from 1961 to 2003.
The total sea level rise from glacier melting were calculated from a global database of glaciers and their mass change over time. Source: Based on graph from National Snowfall and Water ice Data Center
Body of water Level Rise: A Game of Inches
The total amount of bounding main level rise from glacier cook—about 2 centimeters (0.75 inches)—might sound small, but fifty-fifty a couple of inches causes increased flooding in littoral regions like the Bay Area. Every bit glaciers melt faster, the yellow line is getting steeper—body of water level rise is accelerating.
Glaciers naturally fluctuate over time. They accelerate in colder years, and retreat in warmer years. But in recent decades many glaciers have retreated to a stunning extent.
Credit: National Snowfall and Ice Information Center
Muir Glacier, Glacier Bay, Alaska in 1941, 1976, and 2004.
McCarty Glacier, Kenai Fjords National Park, Alaska in 1909 and 2004.
Credit: Lonnie Thousand. Thompson
The retreat of Qori Kalis Glacier in Peru betwixt 1976 and 2004 left behind a large lake.
Earth’s Huge Water ice Sheets Are Shrinking Besides
Glaciers are relatively small ice masses, simply Earth as well has two gigantic ice sheets. They embrace the majority of Greenland and Antarctica. Both of these water ice sheets take been losing mass since 2002, and that melt is accelerating. Like the melting glaciers, that’s causing body of water levels to ascent.
The Greenland ice sheet has lost more than iii,500 gigatonnes of ice since 2002, according to ice mass measurements from NASA’s GRACE satellites. Source: NASA
More Sites Most Glaciers and Ice Sheets
Exploratorium Ice Stories: Traversing the Antarctic Water ice Sheet
Exploratorium Water ice Stories: Measuring a Glacier’s Movement
Fluctuations of Glaciers Browser
Cryosphere and Bounding main Level Rise: From the National Snowfall and Water ice Data Centre
Dataset Example Report: The Breakdown of Larsen B Water ice Shelf
Case Study: The Breakup of Larsen B Ice Shelf
These satellite images from Jan to April 2002, bear witness the collapse of the Larsen B Ice Shelf on the Antarctic Peninsula.
On Jan 31, the ice shelf (left) is dotted with blue pools of meltwater, forming lines to a higher place crevasses in the water ice. A smattering of icebergs appears in the dark, open waters.
By Feb 17, the shelf begins to splinter. The leading edge has retreated nigh 10 kilometers (half dozen miles).
Past February 23, several more long, narrow icebergs have cleaved abroad.
Past March 7, the shelf has disintegrated, filling the bay with a mixture of slush and icebergs. Many of the bergs have toppled over, exposing the very pure blue ice from the bottom of the shelf.
Past Apr 13, the brilliant blue color has faded as the first snows of the season encompass the icebergs. Thinner seasonal ice begins to class, locking almost of the water ice debris in place for the winter. View slideshow at NASA’s Earth Observatory. Source: NASA’s Earth Observatory at Goddard Infinite Flight Centre
The following summer, when the seasonal ice melted, the icebergs began globe-trotting away with the currents. And during many summers since then, the bay has been completely ice-free.
Missing: The Larsen Ice Shelves
The collapsed office of the Larsen B Ice Shelf was larger than the country of Rhode Island. It was the largest in a serial of retreats of the Larsen Water ice Shelf.
Larsen A Ice Shelf, just to the north, collapsed abruptly in 1995. Smaller sections of Larsen B bankrupt away betwixt 1998 and 2002. And Larsen C Water ice Shelf lost the 2d largest single iceberg ever recorded in 2017.
Antarctica has numerous ice shelves. Those on the Antarctic Peninsula accept been shrinking in recent years. Source: Based on maps from NASA.
The Antarctic Peninsula, where the Larsen Ice Shelf is located, has warmed more than the rest of the continent. And scientists believe the collapse of the Larsen B Ice Shelf was at least partly caused by warming temperatures. The rest of Antarctica is cooling, and its largest ice shelves are gaining mass. For example, the Ross Water ice Shelf (south of New Zealand) is thickening as the glacier streams connected to information technology slow down.
What Is an Ice Shelf, Anyway?
An ice shelf is a thick plate of water ice that extends out over the surface of the ocean, and is connected to an ice sheet (state ice) at the shoreline.
Because an water ice shelf is already floating, its disintegration doesn’t immediately make sea levels rise. But an intact water ice shelf pushes back confronting the water ice sheet or glacier behind information technology on the state. And then when the shelf collapses, the ice canvas flows and melts much faster (though still at a glacial pace) into the ocean. And melting ice sheets do increase ocean levels.
More Sites Most Ice Shelves
Exploratorium Ice Stories: Shedding Light on an Ecosystem in the Night
Land of the Cryosphere: Ice Shelves