As we pass through Spring on the way to summer, the sea ice in the Arctic is starting to melt. The ice usually peaks by the end of the first week in March or so, then slowly declines for a few weeks, then by about mid-May is heading rapidly towards its likely September minimum.
With global warming the ice has been reaching a lower winter maximum, and a much lower summer maximum. This is caused by warm air and water, and it contributes to global warming. The more ice on the sea for longer, during the northern Summer, reflects away a certain amount of sunlight. With less ice, less sunlight is reflected away. This is called a “positive feedback” but it is not a “positive” thing. It is a negative thing. (But it is not a “negative feedback,” that’s something different!)
We have seen a steady, but mostly recent, decline in sea ice. For years, climate science deniers have been telling us not to worry, the Arctic ice would come back.
But it hasn’t, and it is not going to.
The National Snow and Ice Data Center keeps track of the amount of sea ice on the Arctic. They have a nifty tool that you can use to plot the data from 1979 to the most recently available information, which is generally a today or yesterday. I used that tool to make a series of graphics I’d like to share with you here. Read the captions to get the key interpretations. The bottom line: Arctic sea ice reduction has accelerated and is not showing any sign of stabilizing.
I’m reminded of a saying allegedly uttered by thoracic surgeons. The bleeding always stops. Eventually. In a similar vein, I assume the reduction of Arctic sea ice will eventually stop. Then the Dinosaurs can live in the Arctic again!.
The chart with no year by year data shown. The grey line is the “baseline” which is usually a 20 or 30 year period against which to measure each year. The grey area is the range over which almost all years occur in this baseline. Since it is two standard deviations that is about 95% of the years within the baseline period. Any year outside of that line is a significant anomaly.These are the first ten years of available data. Notice that during this period, essentially, the 1980s, all the years are above the average for most of the year.As we shift to the next ten year period, 1990 to 1999, the total ice cover throughout the year is less, close to the baseline average.
This trend continues in more recent years, with almost all years being below the baseline average. Remember that second graph above where all the years were above average? That shows that the baseline is set during a period of actual warming, so it is an underestimate of how much ice should be there. And now, during the period 2000 – 2009, all the years have much less ice than this.
This is the third year in a row that maximum sea ice has broken a record for being low.
Large ponderous entities like the IPCC or government agencies like NOAA take forever to make basic statements about climate change, for a variety of reasons. They are going to have to speed up their process or risk losing some relevance. Among the coming problems we anticipate with global warming will be events that have huge, widespread effects and that happen in time scales of weeks or months, or a season, and having a nice governmental report about it two years later isn’t going to do anybody any good. So let’s see to that problem, please (looking sternly at IPCC and NOAA).
But that’s not really what I want to talk about here. Rather, I want to give a wether/climate report that operates at several scales because the information comes to us on several scales and is about stuff that happens at several scales.
Worldwide, 2012 was among the 10 warmest years on record according to the 2012 State of the Climate report released online today by the American Meteorological Society (AMS). The peer-reviewed report, with scientists from NOAA’s National Climatic Data Center in Asheville, N.C., serving as lead editors, was compiled by 384 scientists from 52 countries (highlights, full report). It provides a detailed update on global climate indicators, notable weather events, and other data collected by environmental monitoring stations and instruments on land, sea, ice, and sky.
“Many of the events that made 2012 such an interesting year are part of the long-term trends we see in a changing and varying climate — carbon levels are climbing, sea levels are rising, Arctic sea ice is melting, and our planet as a whole is becoming a warmer place,” said Acting NOAA Administrator Kathryn D. Sullivan, Ph.D. “This annual report is well-researched, well-respected, and well-used; it is a superb example of the timely, actionable climate information that people need from NOAA to help prepare for extremes in our ever-changing environment.”
Conditions in the Arctic were a major story of 2012, with the region experiencing unprecedented change and breaking several records. Sea ice shrank to its smallest “summer minimum” extent since satellite records began 34 years ago. In addition, more than 97 percent of the Greenland ice sheet showed some form of melt during the summer, four times greater than the 1981–2010 average melt extent.
So, here we have two scales of events being reported at one large scale of reporting and study. How does one year stand among more than a century of years, we learn after a year of data collection and 8 months of study and report preparation? What gives in the Arctic over one year in relation to about two or three decades of years, again looked at with months of digestion of a year of data? And, the same report verifies that extreme, often killer, weather (which generally happens over scale of minutes through days) is now normal. So get used to it.
At a somewhat different scale of time, we hear this news from Alaska: The village of Newtok, on the Bering Sea, is being inundated by rising sea levels and they want to move, but political snags seem to be halting the process. This village is probably going to be entirely gone in four years and hardly anybody lives there. This gives us great hope that we will be able to move Boston and New York over the next few decades! (Not)
While we’re still in the Arctic, there is a new study that shows that the Arctic Sea ice as a whole has lost about 15% of its albedo. Here we have a decadal time scale of climate change and a week-long cycle of memic change. First, we had “OMG Santa” with puddles at the North Pole. Then we had “Oh those silly puddles” at the north pole. Now we have the puddles at the north pole being a key factor in the rapid melting of the Arctic Sea ice, which is one of the most significant things going on the Global Warming front now.
And now we are about to experience, it seems, at the scale of a few days an event that may push the current year into infamy among three decades of Arctic Ice melting; a storm is brewing in the Arctic, which together with a wind-generating high pressure system, may blast the ice off much of the Arctic Sea. This is normal … the storms being part of the ice melt. What happens is this: Every time there is a storm or set of storms, the rate of melt goes up and in between stormy periods it slows. You can see this in the minor wiggly-wobbly-ness happening within a given year of Arctic Sea ice melt like in this graph:
Wiggly Wobbly Icy Wisey Stuff
We are about to hit a new wobbly. A big one, I think.
One of the most commonly winged-about facts of Earth’s climate change we hear from science denialists is that sea ice in the Antarctic is increasing, therefore, there is no global warming. The fact that every other measurement of temperature and ice-osity indicates warming and melting would make a normal person think of the Antarctic situation as odd, and seek explanations, but somehow this logic does not emerge in the minds of the denialists. It has been suspected, and increasingly confirmed, for some time that the increase in sea ice in the Antarctic is the result of changes in wind patterns that cause a local increase in ice while at the same time the planet warms. New research from NASA and the British Antarctic Survey adds to this understanding. From a NASA press release:
NASA and British Antarctic Survey scientists have reported the first direct evidence that marked changes to Antarctic sea ice drift caused by changing winds are responsible for observed increases in Antarctic sea ice cover in the past two decades. The results help explain why, unlike the dramatic sea ice losses being reported in the Arctic, Antarctic sea ice cover has increased under the effects of climate change.
Research scientists Ron Kwok of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., and Paul Holland of the Natural Environment Research Council’s British Antarctic Survey, Cambridge, United Kingdom, used maps created by JPL from more than five million individual daily ice-motion measurements. The data, captured over a period of 19 years by four U.S. Defense Meteorological satellites, show, for the first time, long-term changes in sea ice drift around Antarctica.
“Until now, these changes in ice drift were only speculated upon, using computer models of Antarctic winds,” said Holland, lead author of the study published this week in the journal Nature Geosciences. “This study of direct satellite observations shows the complexity of climate change. The total Antarctic sea ice cover is increasing slowly, but individual regions are actually experiencing much larger gains and losses that are almost offsetting each other overall.
“We now know that these regional changes are caused by changes in the winds, which, in turn, affect the ice cover through changes in both ice drift and air temperature,” he continued. “The changes in ice drift also suggest large changes in the ocean surrounding Antarctica, which is very sensitive to the cold and salty water produced by sea ice growth.”
Holland said sea ice around Antarctica is constantly being blown away from the continent by strong northward winds. “Since 1992, this ice drift has changed,” he said. “In some areas, the export of ice away from Antarctica has doubled, while in others it has decreased significantly.”
Sea ice plays a key role in Earth’s environment, reflecting heat from the sun and providing a habitat for marine life. At both poles, sea ice cover is at its minimum during late summer. However, during the winter freeze in Antarctica, this ice cover expands to an area roughly twice the size of Europe. Ranging in thickness from less than three feet (a meter) to several meters, the ice insulates the warm ocean from the frigid atmosphere above.
This new research also helps explain why observed changes in the amount of sea ice cover are so different in the two polar regions. The Arctic has experienced dramatic ice losses in recent decades, while the overall ice extent in the Antarctic has increased slightly. However, this small Antarctic increase is actually the result of much larger regional increases and decreases, which are now shown to be caused by wind-driven changes. In places, increased northward winds have caused the sea ice cover to expand outwards from Antarctica. In contrast, the Arctic Ocean is surrounded by land, so changed winds cannot cause Arctic ice to expand in the same way.
“The Antarctic sea ice cover interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent,” said Kwok.
Climate change has had contrasting impacts across Antarctica in recent decades. The Antarctic Peninsula has warmed as much as anywhere in the Southern Hemisphere, while East Antarctica has shown little change or even a small cooling around the coast. The new research improves understanding of present and future climate change. The authors note it is important to distinguish between the Antarctic Ice Sheet – glacial ice – which is losing volume, and Antarctic sea ice – frozen seawater – which is expanding.
The research was funded by NASA and the Natural Environment Research Council.
Scientists have been measuring sea ice very carefully since 1979. Prior to that, there are estimates that are of varying degrees of usefulness. I know for a fact that many New England lighthouses were attached to land by winter-long ice in places that have not had sea ice in any living person’s memory, and there are similar bits and pieces of historical data suggesting that sea ice was once much more extensive in the Northern Hemisphere than at present.
Since 1979 there have been three years in which Arctic sea ice reached a rather alarming minimum size prior to reforming. We are in one of those years now.
