By Laura Shin
Posting in Cities
In the Arctic, the permafrost is warming, and in some areas, it is thawing. Wildfires in the north are also increasing. How will these changes affect future climate?
Because permafrost's icy soil contains frozen carbon -- mostly organic matter such as leaves and roots -- it releases a lot of carbon, in the form of carbon dioxide and methane, into the atmosphere as it thaws.
Scientists, who are now observing how much of these gases are currently being released from this thawing ground, say that the most worrying part about a warming permafrost is that if the permafrost begins to thaw, it will be impossible to stop.
And if the thawing of the permafrost is not stopped, that will release vast amounts of carbon into the air. Scientists estimate that the permafrost contains two and a half times as much carbon as the entire atmosphere. Current projections for the amount of carbon that the Arctic and sub-Arctic regions could one day annually contribute to the atmosphere are equivalent to anywhere from 15% to 35% of today's yearly emissions from human activity.
“Even if it’s 5 or 10 percent of today’s emissions, it’s exceptionally worrying, and 30 percent is humongous,” Josep G. Canadell, a scientist in Australia who runs a global program to monitor greenhouse gases, told The New York Times. “It will be a chronic source of emissions that will last hundreds of years.”
Likely to exacerbate the problem are two facts: First, methane, which is often released by thawing permafrost, is more than 20 times more effective than carbon dioxide at trapping heat in the atmosphere. Second, wildfires are becoming increasingly common across the north, and increased burning will further the thawing of the permafrost.
Permafrost ancient and recent history
During the last ice age, western North America and eastern Siberia were not covered in glaciers, but powerful winds and rivers brought in massive amounts of silt and dust to these frigid areas. During the summers, the top layer of this soil would thaw and grasses would grow and take in carbon dioxide. During the winter, organic materials such as grass roots, leaves and even animal bodies would freeze before they could decompose, forming layers of permafrost.
In the last several decades, scientists have been logging permafrost temperatures, and the overall trend is clear: temperatures are rising relentlessly across the region and the northernmost regions are warming the fastest, while the southern areas have shown marked thawing. For instance, the permafrost across much of central Alaska is just below freezing and should see widespread thawing as soon as the 2020s. In the northern regions, the permafrost is still 12 degrees Fahrenheit below freezing.
Scientists are beginning to worry that the thawing of the permafrost changing the land more rapidly than they can understand the changes or make predictions based on them. For example, the region is seeing an increase in a particular land phenomenon called thermokarsts (photographed above).
Thermokarsts form when the thawing permafrost ground turns mushy, causing the land to collapse and often causing a lake or wetland to form. The dark surface of the lake's water will then capture more heat from the sun and cause the surrounding permafrost to thaw as well. Near thermokarsts, the forests often are called "drunken," because the trees, whose roots have lost their solid support system, lean crazily.
Thermokarsts are becoming more common in some regions, such as northernmost Alaska, but scientists are not yet sure whether they will become more common throughout the Arctic.
“We expect increased thermokarst activity could be a very strong effect, but we don’t really know,” Guido Grosse, a University of Alaska, Fairbanks scientist, told The New York Times. He is working with another scientist on mapping thermokarst lakes and methane seeps to see if satellites and aerial photography can be used to detect trends.
The roles of methane and wildfires
The first reason the thawing of the permafrost is especially worrisome has to do with methane.
When the permafrost thaws, the organic material trapped in it is consumed by bacteria. If there is air in the area, oxygen-breathing bacteria will break down the organic matter and the carbon will enter the air as carbon dioxide.
But when organic matter breaks down at the bottom of a lake or wetland, then another type of bacteria (methanogens) will break it down, releasing the carbon into the atmosphere as methane.
Although most of the carbon released by the permafrost is likely to be carbon dioxide, scientists say that the fact that methane is so much more potent than carbon dioxide as a greenhouse gas means that it will be likely be responsible for trapping as much heat as the carbon dioxide will.
Another reason scientists are concerned about the thawing of the permafrost is the fact that fires in the tundra are becoming more common as the land, which used to be too damp to burn, dries out.
A 2007 lightning-sparked fire on the Anaktuvuk River in northern Alaska was the first of its size (400 square miles) in 5,000 years. As the Times reports,
Scientists have calculated that the fire and its aftermath sent a huge pulse of carbon into the air — as much as would be emitted in two years by a city the size of Miami. Scientists say the fire thawed the upper layer of permafrost and set off what they fear will be permanent shifts in the landscape.
The paper quotes Michelle C. Mack, a University of Florida scientist who is studying the fire: “I maintain that the fastest way you’re going to lose permafrost and release permafrost carbon to the atmosphere is increasing fire frequency."
It's not entirely clear exactly how these changes will impact the Arctic, the permafrost or the planet as a whole. For instance, the thawing permafrost could release nutrients that spur more Arctic plant growth, and those plants then take up some carbon dioxide.
But the scientists studying the area are worried by all the changes.
“To me, it’s a spine-tingling feeling, if it’s really old carbon that hasn’t been in the air for a long time, and now it’s entering the air,” Edward A. G. Schuur, a University of Florida researcher who has done much research in Alaska, told The Times. “That’s the fingerprint of a major disruption, and we aren’t going to be able to turn it off someday.”
photo: The land around these two bays in Northern Siberia is dotted with thermokarst lakes. (NASA Goddard Photo and Video/Flickr)
via: The New York Times
Dec 18, 2011
I find it confusing that cooling global temperatures brought on by a natural change in solar activity reducing the amount of water evaporation and impacting rain fall is universally accepted as the cause for the sudden expansion of the Sahara Desert over 10,000 years ago, yet when applied to events in other parts of the planet they are shrugged off as non-events. It is no big deal when geologists say the Sahara has gone through such cycles in the past and will return to a more savanna like environment as the earth naturally warms from the changing solar cycles, yet those same natural temperature changes are blamed on humans when talking about glaciers in Greenland. It needs to be reminded that Greenland is called such because it was largely green in the early history of man living there. From a planetary history standpoint, being covered in ice is the recent reoccurrence of a long running cycle.
I see a lot of guys glibly assuming the thawing of permafrost will not be a bad thing and that a warming world will be good for us. I see a bunch of anecdotes with little or no scientific backing and that completely ignore the time scale that it will happen on. What I don't see is any scientific basis for your beliefs, just a lot of speculation that it won't be so bad.
Let's see... "During the last ice age..." the earth was much colder than today, and it has been warming ever since. More lakes... more wetlands... more vegatation that takes in CO2 and produces more oxygen... and yet, somehow, these things are bad.
Being a Canadian you must know how extensive the melting was in the 1850s when difficult to maneuver sailing ships nearly made it through the Northwest Passage? While the sea ice melted, on shore the permafrost was not so permanent then either. Surely you know that the Canadian military established extreme northern military bases and harbors in the mid 1800s that they are now considering reopening for the first time since WW II.
It's indisputable that there was more vegetation at times in our distant past. Coal is thought to have formed 400 million years ago from vegetation on land, and we're not producing significant amounts now. Oil formed from plant and animal life in the shallow seas of 200 million or so years ago. It's believed that during these times the earth was as much as 7 degF hotter than it is now, which is about double the rise expected this century. Global warming, whether man-made or not, will not destroy life on this planet. It may even result in more life than we have now. But it will require massive adjustments by humans. However, if you look at the changes in civilization during the past 200 years or so, it's clear we can do it if we need to.
... this is an interesting read with many counter points to the delusional global warming rants we so often hear. http://joannenova.com.au/2010/02/the-big-picture-65-million-years-of-temperature-swings/
Uncertainty is the worry! New understandings may just now be coming from the Japanese IBUKI Satellite (via Google), launched in 2009, with first published data Oct. 29, 2011. The objective is to monitor the "flux" of CO2 and methane around the earth. I believe "flux" means the addition or depletion of GHG at any location and time which changes the concentration in the overlying atmosphere. It is so startling to see the impact of the boreal forest in reducing CO2 during its short growing season. The forested areas reduce CO2 by 10% or about 30 ppm in a few short months. The range is currently 390 ppm down to 360 ppm. On the other hand, tropical areas see little or no impact, as the vigorous plant growth is apparently matched by an equal vegetation rot! Boreal forests are the land-part of the "lungs of the earth". Perhaps the absorption of the sun's energy by photosynthesis is more effective than the reflection back to space by ice and snow cover? As the permafrost thaws, the boreal forest is expanding north. Which effect will predominate? (I hope this gets submitted this third time around, as I kept clicking on the giant "Add your opinion" icon and my message just disappeared! Then I found the dinky little "Submit" button!)
No joking here, just an honest question. We find much plant and animal remains in these frozen (permafrost) areas. We know that life on this planet was much more abundant in the past - and that these frozen areas were once vast green grasslands. If life was so much more abundant (in all forms from bacteria through mammoths) what's wrong with global warming? Who are we to be so upset about loosing beach-front property that we're willing to attempt to "mess" with natural cooling/warming cycles? Who do we think we are?!
The end of the last glaciation was 10,000-12,000 years ago. Temperatures hit a maximum during the Holocene Climate Optimum about 8,000 years ago and have been slowly declining since then, until the recent sharp rise that is.
Another real, thinking individual. A temperature rise on this planet could be really good for life here! Sure we'd have to adjust as people - but we're the best suited to do it - and also dislike it the most. Sad how so many are so mislead - really.
Anyone who references "clamategate" as truth cannot be taken seriously. Especially coming from a former(?) Shell employee. Check your sources. Besides that it's called permafrost because it's ground that is permanently frozen. I live in Saskatchewan and it hasn't stayed below freezing for a full week yet and it's been like that for a few years. I can see Global Warming first hand and it's undeniable.
I take you back to the carboniferous era - the time when all our vast coal deposits were laid down. All the 'temperate' regions of the planet were covered in vast forests, of strange primitive trees like monkey-puzzles and cycads, huge ferns. Temperatures were on _average_ 10C (18F) higher, some say, some say more, maybe 15C or more higher than now ON AVERAGE, and that means peaks of temperature 30C higher than now. There was no ice at the poles. The atmosphere was GREAT for plants - it was loaded with carbon dioxide, maybe 3-5% or more. It was not good for large mammals or large animals in general - there were none. There were huge insects, though. If I plunged you into that world you would be dead very soon. For a start, you begin to breathe very quickly in a high-CO2 atmosphere - your breathing rate is regulated by the amount of CO2 in your blood, not the amount of oxygen - and you develop severe acidosis, which would lead to organ failure and kill you quickly if you didn't die of heatstroke first. This is not a world suitable for humans. We don't want to get anywhere near there. But that's where we are going if we just blindly carry on as usual.
Air warms up - seas warm up - ice melts - high volume of fresh water enters the northern oceans - sea levels rise - ocean currents such as the Gulf Stream/Atlantic Conveyor stop delivering their benefits northwards - northern latitudes such as Europe and Western N America cool down, while southern latitudes get drier and hotter, plus many other induced changes to flora and fauna, including our weather systems and our agriculture - on all of which we are dependent. Current civilisation has to adjust to this rapidly or follow the dinosaurs and mammoths into extinction, whilst in the midst of a population explosion demanding more food and water. Does that equation look comfortable to you, whether you happen to live on a beach front or not? Anyway, where does it say that life was so much more abundant before? And just when was that? Certainly a good deal has already been killed off directly or indirectly by human activity. But life is not going to exist in either hot or cold deserts in any volume. So where would it find a home if your logic somehow works? What's wrong? Humans have adjusted quite well to a wide range of climate in the past, in limited numbers. But only with the aid of resources and within limitations. So a diminishing supply of those is not going to support today's 7 Billion+ humans or more in extreme conditions. Or maybe you have an answer to your own 'honest question'. No joking!
it'll be final all right. Millions will die. In 2010 thousands died in Russia's heatwave, and that was a result of merely a little bit more heat in summer. Do you eat bread? Watch the price go up. Do you eat meat? What does 'meat' eat? Large parts of the U.S. were on fire last summer, and the parts that weren't, where they'd normaly grow wheat and corn, were too dry to get a decent crop. You are deluded. Wake up.
During the mid 1800s the fabled Northwest Passage was nearly crossed by sailing ships. It was that ice free. One such exploring ship, the HMS Investigator, was found in Mercy Bay in 2011. A place where, until recently, global warming scientists had told us had been a frozen wasteland for centuries. Completely impassable to ships until the recent melting. Obviously they were wrong. The story of how it got there is most interesting. http://www.cbc.ca/news/technology/story/2010/07/28/hms-investigator-arctic.html