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Ponter Boddit

I would have thought the more trees sucking in CO2 the better. Why is this?


The story claims it's about albedo. I presume the longer explanation is that it takes more snow to cover up trees and shrubs than to cover up shrubs and mosses?

Steve Bloom

The albedo effect is larger than any CO2 sequestration benefit, especially locally (since the CO2 is effectively drawn from the whole atmosphere).

Vegetation that's taller than the snow is deep doesn't get covered very well.

Steve Bloom

Just to add, this makes three Arctic land feedbacks that have had their warming effect calculated substantially upward recently: Vegetation, permafrost and microbial activity. GCM results for the Arctic don't include these at all since they're slow feedbacks, and to my knowledge ESM (earth system model) results have incorporated only the permafrost, and that only by way of the calculation in the paper describing the increase in the effect. And of course these three feedbacks will feed back on each other, so it will be interesting to see how the effects are handled.

James Dunlap

Ponter. One of the reasons is that any vegetation which is higher than the snow level catches the sun more directly due to its being perpendicular to the level of the ground. Plus all vegetation is dark and has a low albedo. Thus it warms very fast compared to its surroundings. You see this effect at any time of the year when the temperatures near freezing in the direct sun. There will be significantly greater snow melting right around the bush or tree. Sort of like a hole in the snow. This results in the ground around the vegetation becoming snow free much sooner than nearby areas that have no vegetation and it gets much warmer. The bushes and small trees then grow much quicker and have a tendency to spread faster. One of those amplifying feedbacks that we are always talking about. I have seen pictures of places in the arctic taken of the same location about 30-40 years apart and there are small forests now where there used to be bare tundra.

Shared Humanity

Always looking for a silver lining....given we have already past the point of avoiding severe warming, we can only hope a greener north will expand the areas for agriculture. It might allow us to avoid a massive die off of humans in the next 100 years.

Ac A


"It might allow us to avoid a massive die off of humans in the next 100 years."

Well, who knows... but do not forget resource depletion and the fact, that climate change is only ONE of MANY global problems...


Chris Reynolds

Taller plants will, as has been noted above, increase albedo. This will increase local warming, and plant roots may help to break up deeper permafrost.

James Dunlap

SH, Your hope for such a silver lining as the north warms is s common one. Unfortunately it is often also used by the camp of folks who subscribe to the belief that such new northern agricultural areas will offset the loss in the temperate regions and that we do not need to take action now. Unfortunately the ground truth says that it will not work out that way. There are several factors which will prevent it from working to our advantage. Among them are: The soils of Canada and Russia are not the high quality loams required for extremely high yield production (not to mention that they amount to a lot less acreage). You could not get American midwest production out of them even if they were located in a proper latitude for high production. Which, of course, they are not. Other issues you will have to deal with are the freeze and frost problems. Even with a warming climate you will not get as wide a range of frost free days as you would farther south. And you would still get the occasional early/late season unexpected cold snaps that would hurt production. There is no substitute for a long string of warm frost free days if you are trying to grow on a vast scale. One cannot replicate the micro climate found in the valley in Alaska where they grow the giant cabbages across the whole arctic. Lastly, the amount of sunlight available during the growing season, for the various vegetable plants we grow, at high latitudes is not what the plants evolved to expect and this will in many cases not be optimum either. Another item, not related to latitude, is that studies have shown that as CO2 levels rise the overall productivity of our food plants will decline not rise. And, if you run into one of the folks who think that we will feed everyone by a vast network of hydroponic greenhouses just ask them where they are going to get the resources to build and maintain them. Hydroponics are like industrial agriculture on steroids.


Yet another positive feedback, as has already been noted. I do not think that the extra CO2 sequestered by this new growth will balance the extra warming. The growing season will be short and the light intensity will be less than nearer the equator. Meanwhile, the increased albedo and likely release of carbon, both as CO2 and methane, will easily outweigh any CO2 sequestered by this extra growth.

Ac A


"the increased albedo and likely release of carbon, both as CO2 and methane, will easily outweigh any CO2 sequestered by this extra growth"

- yes, there are studies to confirm this:

Vulnerability of Permafrost Carbon to Climate Change:
Implications for the Global Carbon Cycle

tundra-to-forest --> -4.5 kg C m-2; permafrost-to-non-permafrost --> +35 kg C m-2


Robert Fanney

Yep. Just one more positive feedback. I suppose one can hot that desertification increases albedo... Not funny, I know.


[quote]I would have thought the more trees sucking in CO2 the better. Why is this?[/quote]

Short answers:

1, Albedo feedback is responsible for somewhere between 1/2 and 3/4 of the total forcing.

2, Carbon absorbed by some relatively small amount of greening isn't going to stop the positive slope in the keeling curve, particularly since plants produce waste every winter anyway when grasses die and trees lose their leaves and such, which offsets much of the absorption benefits.


The story claims it's about albedo. I presume the longer explanation is that it takes more snow to cover up trees and shrubs than to cover up shrubs and mosses?


Melting day anomaly is what will allow the greening. This means there are fewer days with ice or snow packs. This is what really does the damage.

Green is better than dark soil, but worse than snow.

It is also possible that the wind could blow light snow accumulation out of the tree boughs, which would expose more green than mosses or shrubs, but I don't think that's the biggest problem. I think the main problem is just the snow line retreating more and more.

Fairfax Climate Watch

There's also way too much carbon frozen in the soil - as the Arctic thaws, plant growth will offsets soil carbon loss, but only for a very brief time after thaw sets in for a given location.

Fairfax Climate Watch

Depending on the vegetation type, there is more or less air pockets in snow cover...so that is also an issue (insulation).

Michael Fliss

Chris & Syddbridges,

Wouldn't plant growth decrease albedo which increases warming? As you know, a darker surface reflects less light and has a lower albedo.

Steve Bloom

D, these things are actually subject to calculations based on observations, which I expect was done for this paper. But one factor you seem to be missing is that a relatively flat surface is a much better reflector than a bumpy one since the latter has much more reflection at odd angles and so increases absorption.

Steve Bloom

Also, for much of the year at those latitudes albedo is either zero or small. For much of the remaining part there is little or no snow.

Steve Bloom

For cropland to replace that degraded by heat and drought, SH, one needs acceptable soil and water. Especially the former will be hard to come by, as with e.g. the Canadian shield, and drought is bound to affect some of those regions as well. In addition, many crops won't do so well with the vastly different insolation cycle at those latitudes.

Eli Rabett

This is more about the treeline moving north than greening from ground plants. Trees far up in the new northern forests will be evergreens. The needles will contribute to warming throughout the year, both in absorbing sunlight through the spring, summer and fall, but also in insulating the ground during all seasons.


I had an exchange of emails with Govindasamy Bala of the Lawrence Livermore National Laboratory in 2007. My summary of his view after a few emails was

1. Planting (or keeping) trees in tropical regions is good.

2. Planting trees in snowy areas is bad.

3. Planting trees in other areas may be good or bad.

His response was

Points 1 and 2 are ok.

Point 3 should be "planting trees in other areas may offer little benefit."

The LLNL press release in 2007 was https://www.llnl.gov/news/newsreleases/2007/NR-07-04-03.html

The situation is clearly complex. There are lots of other considerations e.g. if cities are cooled by trees will the energy use fall? http://www.fs.fed.us/psw/programs/uesd/uep/products/psw_cufr684_TreesAndGHG.pdf

Trying to make the case for the use of wood, I had made this point to Bala at the time ...

"I may have not made clear my concerns about the 'short term'. I am not suggesting that it is possible to stop climate change quickly. What I ask is "Will we need to bring in emergency, short term, measures to cut the carbon burden on the atmosphere?" For example, should much more biomass be used in the construction industry to lock up carbon in the fabric of buildings so it is stored for the lifetime of the building at least. I have heard that significant positive feedbacks have not yet been incorporated in the appropriate climate models (e.g. methane from the tundra) and that we may have an acceleration of climate change. Does this mean a tonne of carbon dioxide released now has a worse effect than one in a hundred years time? Do we need to think of emergency measures to buy time?"

This is a big topic. Should it be on the Forum?

Andy Lee Robinson

I noticed a slip above - higher albedo means higher reflectivity.
Therefore more trees, less albedo, less reflection, more absorption.

Steve Bloom

Open a topic, Geoff, and note that there's been a huge amount of research on the subject in the intervening 6 years. It would be interesting to ask Bala how his views have changed.

See this but also this, both published very recently. My impression from these and other results from the last few years is that new forests are a net plus with the benefit tapering off over time, but that the negative impact of a warming climate on existing forests is far larger.

Steve Bloom

Eli, the paper is clear that expansion of shrubs north of the tree line is also important.

Steve Bloom

Eli, the paper is clear that expansion of shrubs north of the tree line is also important.

Steve Bloom

And this recent paper (press release) provides some context.


I released a couple of comments from the spam filter. I don't know what's wrong, but am getting increasingly annoyed. Spam is one thing, perfectly legitimate comments getting tagged as spam is quite another. My apologies for the inconvenience.


Move along people, nothing to see here. In Sept 2012, John Gummer -- the UK ag minister who deliberately exposed his 4-year old daughter Cordelia to mad cow disease -- became Chairman of the UK's independent Committee on Climate Change. I scarcely think we need concern ourselves about Arctic vegetation with a leader of this integrity in place.

 photo gummerLast_zps72618048.png


I recall that larch and black spruce are the dominant conifers in the massive boreal forests of Russia and Canada. These constitute the northerly expanding tree line.

Larch are deciduous. The needles turn yellow in the fall and drop off in the winter. They do not put out new growth in the spring until mean temperatures are above freezing and length of day is substantial. Considerations of albedo must accommodate this twist.

I was up in southern Saskatchewan this summer looking at a rare exposure of the Chicxulub. I came to regret purchasing a provincial road map because it turns out they have no roads of any kind in the northern third.

In fact, it is impossible to drive to the Northwest Territorites from Saskatchewan and even if you somehow could arrive in an amphibious vehicle, there would be no roads of any kind when you got there. I believe it is boglands the whole way rather than the scraped pre-Cambrian shield to the east, or the Rocky Mtns and nitrogen-depleted rain forests to the west.

The Canadians have had about every square meter of arable land under production since the 19th century. Farming in the far north entails bringing trainloads of soil up from Iowa, auguring giant soil wells in the rock, draining landscape-scale wetlands with massive pumps, offseting peat acidity with vast carbonate mines, genetically engineering cereals to the exotic photoperiod and wild swings in temperature, and so forth.

Not going to happen. And even if it did, the little grain produced would still go to beef for the rich man's barbeque and ethanol for his Hummer, as it does today.


It may not be a good idea to expect crumbs from the table of the corporate masters as climate change sets in. They are already quite inured to early death in the peasantry, climate change is simply more of the same. Overall market size may decline, but shortages can justify more-than-compensatory price increase. We're not all in this together.

The World Health Organization factbook states that some 156,000 people die every day or 57,000,000 per year. A third of these deaths are not age-related in any way. In fact, it's claimed a child under five dies every 5 seconds as a direct or indirect result of poor nutrition.

I'm fascinating by the glass-half-full posts here on the Arctic opening to shipping, leading to a bonanza of cheap goods, plasma tvs and toyotas too cheap to meter. Actually, Maersk will simply pocket the savings. They're not a charity.

Jim Hunt

Hi A-Team,

I recently emailed a link to NASA's latest images of the Arctic to the UK's Department of Energy and Climate Change:


Here is their official response:

"In answer to your question, there is increasing evidence that melting Arctic sea-ice may affect Northern Hemisphere weather patterns by influencing the position of the jet stream. Many other factors also play a part in determining weather in the UK and Europe.

In particular, warm North Atlantic sea surface temperatures (as we are currently experiencing) are connected with above average summer rainfall in the UK."

They made no mention of what they intend to do about this sorry state of affairs.

Shared Humanity

They made no mention of what they intend to do about this sorry state of affairs.

Recent statements released indicate they are planning on purchasing and distributing "top of the line" bumbershoots.

Steve Bloom

Thanks for expanding on those points, A-Team.

Another relevant forest paper just appeared.

"In particular, warm North Atlantic sea surface temperatures (as we are currently experiencing) are connected with above average summer rainfall in the UK."

Evasive, isn't it?


i'm no fan of gummer, who was, and no doubt still is, an idiot, but this:

'UK ag minister who deliberately exposed his 4-year old daughter Cordelia to mad cow disease'

is misleading to the point of being a barefaced lie. seriously not cool


Don’t really know where to post this…

But, each year I lay out my garden with a new theme. This year, the theme will be the “Beaufort break-up”. I will lay out parallel curved footpaths to symbolize the new cracks, and since it will soon be sowing time here, I also plan to let tall green plants in one end symbolize the advancing tundra vegetation. I do however have difficulties finding plants, which can create the image of melt pools on the remaining ice floes. Any good ideas – preferably something edible, which can withstand both droughts and floods during the summer?


How about just a big pond, P-maker? ;-)

Jim Williams

I know. Off topic...

One of the decorative sages is just slightly greener than the borders of this blog P-maker. Not sure what its name is.


I'm a little leery at diving into this pond, at risk of failing to keep up with comments, added to all the other stuff I should be doing...

In another lifetime, as my first adult scientist experience, I studied arctic ecology at/near Barrow, AK in the early 70's. A primary interest was the distribution of plant types by microclimates and ecotones/ecoclines... There's a whole nother language.

The simple summary: It's complicated.

The high arctic is?was a desert, with less than 8 inches of precip per year, on very flat plains, where a meter high ridge line can be seen three to four miles away. Whole plant communities are determined by height above the permafrost/water table level. That interface is not only the primary source of liquid water, but also the place where nutrients are found. Nobody grows in the winter, which is/was 9 months/yr. We took aerial photos of the plants in full summer, and could map out the microelevation changes by colors of the plant communities.

At that point in time, the local ecology was still relatively stable, kind of the end stage of 'the old days', I'm guessing.

Major limiting factors include water, nutrients, and winter cold. Shrubs look more like trees where they are protected by being buried under the snow in winter (a drainage cut along a river bank) - being above the snow exposes to brutal winds and the occasional browsing caribou herd.

Northern forests are limited in extent at the edges by the arctic winds, and have to expand from center out, creating a critical mass wind buffer as they go (almost entirely by underground tillering from older plants - not much useful plant sex in the far north).

In the winter, everything is white with frost or snow, and there's no sun anyway. The albedo effects are limited to the summer growing season, which is pretty short, though one impact here is any extension on that season length. The albedo impacts permafrost depth, which is a huge issue, since there lies all those nutrients, water, and that sequestered carbon.

In summer, the ground above the permafrost is saturated with water, and is mostly peat of some form (all that carbon), with variable density. You can't drive vehicles over most of this without destroying the surface, leaving linear tracks of black water that become rivers over time as the albedo melts the sidewalls...

Muskeg is the swampy forestland that extends fingers up from the south. That ground is similarly saturated over frozen peat, with short stubby fir trees that point every which way around the dead that lie in herringboned disarray. You can't walk in that stuff, let alone drive through. Roads are major messes, that re-route water, and require constant maintenance (and turn to jelly with earthquakes). Off road vehicles tear the place to pieces, see above.

Not gonna be much agriculture in that world, except as slow encroachment from the edges.



I certainly hope the above piece is posted on the Forum as a Topic of it's own. This was very valuable and important information to be shared with another audience.

Lewis Cleverdon

A further feedback seems predictable from the expansion of thermokarst pool terrains and also landslip dam-lakes interacting with the increasing prevalence of deciduous shrubs and tree species over what had previously been essentially tundra grasses, sedges, etc.

Positing 5Ts dry matter in the leaf-fall per hectare would give around 2.5MTs Carbon per MHa (10,000km2). Unlike dead grasses dead leaves are shed and will tend to blow across open country, with pools being a prime trap for them. For each megatonne of leaf-carbon entering the pools and rotting anaerobically, there is a potential emission of 1.25MTs CH4.

With the same volume of carbon rotting aerobically to 3.664MTs CO2, and CH4 having around 100 times the GWP of CO2 over the critical 20-year time horizon, deciduous leaves rotting anaerobically would raise their carbon outputs' CO2e value about 34-fold.

The significance of this potential feedback depends on the areas of permafrost going to open water and to deciduous plant cover, as well as on their proximity. Notably the potential land areas are very large indeed.

Should anyone find studies relating to this aspect of the arctic problematique I'd be much obliged if they'd post a link.




A month out of date, but just heard about it.
The Keeling curve hit 400 May 9th.
http://www.livescience.com/29437-carbon-dioxide-record-broken.html talks about record.
http://keelingcurve.ucsd.edu/now-what/ talks about what it will take to stop/slow things down.
As jelly fish seem to be one of the few things that can survive in high acid/CO2 water may need to GM one to create O2.



Heh. Its not things to make oh-2... it's things to *eat* the things that make oh-2. Acid water is relative; there's lots of stuff that will survive just fine. Key problem will be for species with external CACO3 shells that have difficulty. Interestingly, if they use Mg, they won't have quite so much trouble.

We need stuff to eat the algae, otherwise, we get eutrophic and anerobic environments, with related releases of H2S and similarly obnoxious emissions.(As happened at a couple of junctures, last of which was about 65MY BP, if I recall...)

Jellyfish however present their own problems; they can have devastating impact on the fry and 'larval' stages of many species. To deal with them, we need stuff (like molluscs) to filter out *their* fry, or more turtles and sunfish to eat the adult versions.

Just another of those things we'll need to figure out how to manage, as a result of throwing wrenches into the gears.

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