Positive feedback raises potential warming by another 2C 22 May 06

Coupled with another record low for the Artic Sea ice (there is some interesting commentary on Real Climate about the extraordinary temperatures recorded over the last few months at Svalbard, north of Norway)this is yet more evidence that matters are and will proceed faster than anticipated.

One factor that interests me, and on which I have seen little comment for some time, is just how long is the time lag between a certain level of greenhouse gases being reached in the atmosphere and the resulting temperature increase feeding through?-50 years was the last estimate I saw. That is a long time in human terms and emphasises how emissions today will have ramifications for decades as the temperature rises setting off further feedbacks.

At times, on this blog, I have suggested that the heat imbalance of the earth be the prime focus and when this is done then 2 other strategies emerge which can complement emission-reduction strategies. These other 2 strategies are transferring surface heat to the ocean depths and reflective strategies utilizing the atmosphere, land, and space to reflect excess solar energy away.

The transfer of energy to a heat sink is best done by utilizing the thermal-gradient between surface and ocean depths to produce electricity and fresh water. The thermal efficiencies are low making this difficult but a side benefit “never mentioned” is the reduction in surface sea temperatures that can actually have a real effect if this energy source is widely used. I did a few calculations on it and the side benefit helps reduce surface heat by bringing up vast quantities of cold water from the ocean depths.

Still, the main focus of this technology is renewable electricity with no greenhouse gases. The ocean-surface heat extraction benefit makes this renewable resource less than net-zero equivalent emissions. The ocean thermal gradient systems are explained in the sites below:

http://www.nrel.gov/otec/what.html

http://pesn.com/2006/01/04/9600218_Sea_Solar_Power/

I will make 2 comments about the “unmentioned” side benefit I am talking about with regard to lowering sea-surface temperatures.

First, the thermal efficiency of this system is low with less than 10 percent of the energy in the thermal gradient creating electricity. The overwhelming greater than 90 percent of the energy simply is transferred to the cold water brought up from the deep ocean. The heat energy reduction of the sea surface is over ten times the energy from the electricity produced. This is a “measurable” contribution to lowering global warming if this technology is widely used.

Second, the oceans have a tremendous capacity to store heat as compared to the troposphere. A liter of water can store more heat energy than a liter of air. We all know this. Based on the thermodynamics of the earth’s heat imbalance measured at 0.85 watts per square meter, it would take 6 centuries for global warming to raise the entire ocean 1 degree Celsius.

This would be a tenth of a degree when applied to the next 60 years. Since this technology would present a much smaller fraction of this, then the effect on the temperature of the ocean would be negligible. In fact, the oceans rise in temperature anyway so this idea only mixes a very small portion of ocean reducing the surface heat a little more than nature would do naturally.

Ocean thermal gradient systems work best in tropical waters. This additional benefit will not influence the positive feedback occurring at the North Polar Region.

In the industrialized urban areas, I think it is common sense to abandon the use of black tarmac for roads, roofs, and parking lots. There is a significant area over 100,000 square kilometers of dark absorbing surface in the USA alone which can be made more reflective with the correct aggregate used in the cement mix. Doing this not only will reflect solar energy back into space on sunny days, but it will reduce heat island effects which reduce peak cooling loads which then reduce the need for more power plants. The reduced energy used for cooling will also reduce greenhouse gases from fossil-fuel electricity.

Finally, we have the Arctic area which in my mind has become desperate. It is desperate because the positive feedback loops are taking over regardless of any realistic emission-reduction strategy we can conceive. I can back that statement up! Also, the threat to permafrost melting and releasing huge quantities of GHGs suggest drastic action is required. Remember, this positive feedback loop is driven mostly because of the current greenhouse-gas buildup and not the current emissions we are producing.

There are atmospheric reflective strategies which may be more pragmatic in terms of implementation. These include seeded the atmosphere with sulfates imitating the effect of a volcano. I think we have to keep an open mind about all options but I have a personal bias against them only because of the pollution they cause. In that light, I share this bias and this is why I do not expand upon this strategy. I mention it because it may be a viable option we may have to consider. I hope others expand on it since we have to thoroughly assess all options objectively.

Outer space offers another place and I do have a personal bias for it for a few reasons. My main attraction to the concept is its flexibility on reflecting solar energy anywhere on the planet with precise control from the ground. It is non-polluting as well. It is a counter strategy to the positive polar feedback loop we created.

Lightweight structures of large areas can be created in space because there is no gravity to contend with. These structures can be placed in orbit and precisely controlled from the ground as to location and orientation to the sun. Once in orbit, they can remain a tool to help reflect solar energy away and for me targeting the sensitive polar areas would be a first priority.

The big idea in using a space mirror is to offset the increased summer-time solar absorption in the Arctic Ocean, in particular, due to the loss of reflective of summer ice. This focus is meant to slow down the ice-melt to help us buy time to make the long-term emission reductions work.

If successful, the permafrost would remain frozen, and the arctic stabilize at some level. With further reductions in GHGs, the heat loss to space during the dark winter months will increase and allow the ice to regenerate.

In the distant future, the space mirrors can be oriented just like a thermostat to help complement natural and manmade influences on the climate. By then, we will have learned much more than we currently know about the climate.

There is another side benefit to this unique focus. It would help increase climate research. I say this because this focus demands more research to insure the success of the costly mission. It still has to be modeled before hardware is even designed. This would promote better computer modeling to assess various orbital configurations and the amount of mirror surface area required. The idea still has to be proven as to how it can offset polar melting. The main downside of course is the cost and difficulty of such a project.

I know many who would like to believe we have an easy way through this problem and may think those proposing reflective strategies believe it would get us off the hook on emission reductions. In my mind, we need both. I also think any opposition to reflective strategies would come from those opposed to reduction strategies from the same economic arguments of cost effectiveness.

My points have nothing to do about costs and everything to do about being successful. We have to be successful in our thinking if we do anything at all. We have to insure our success through the use of multiple options which can transcend all uncertainties of any worst-case scenarios.

In my mind, only if the emission strategy actually “reduced” the current carbon buildup significantly within 2 decades would we have a chance. Right now, we cannot even slow the buildup each year so we have a long ways to go. On the emission side of the equation, I would focus on radical methane reductions over carbon because this would have the best short-term benefit. At the same time, the carbon would still have to be reduced below the carbon buildup level as well.

Looking at this pragmatically, I think we have to do everything. This is a fight for survival my friends and so we are lucky to have any options we can use. Ignoring something which has the potential to help may be the biggest mistake of all.

The most prudent course of action is to be prepared to move quickly. All strategies need to be investigated and evaluated together to assess their combined effect. If ideas can reduce greenhouse gases and offer another modality such as solar reflection, then the total cost/benefits need to be evaluated as a system.

Please feel free to comment. The dialogue created always advances our thinking forward. That is what Mark’s blog is all about. Please feel free to challenge, confirm, or suggest other ideas. Your statement helps advance the consensus of how we can stop the polar ice from melting further and the runaway effect of melting permafrost? How can we win? We have to create a successful plan with a guarantee!

One other comment about reflective strategies is that they offset some of the current greenhouse gas buildup immediately when implemented. Only until emission strategies can actually reduce the greenhouse gas buildup can they make this claim. So far, greenhouse gases continue to increase and how much melting permafrost will contribute may further make the case that we need to think about additional measures.

Best regards to everyone,

Dan

PS Proof of the Arctic urgency below:

This link below was given to me by another person on this blog a while back. Thanks!

http://www.nasa.gov/centers/goddard/news/topstory/2005/arcticice_decline.html

Please note that the graphs in the link above show that a significant portion of the summer ice which melted did not regenerate in the winter in the last few years. This is due in part from the fact the solar absorption is 10-fold higher from the decreased albedo plus the lack of ice allows more absorption.

Ice absorbs much heat energy in order to melt it. One cubic kilometer of ice-melt absorbs the same heat energy which can raise 80 cubic kilometers of ocean water 1 degree Celsius. This is from basic physics. It is called the “latent heat of fusion” of water.

In other words, if you have frozen food, it takes as much heat energy to thaw it as to raise its temperature 80 degrees Celsius once thawed. Think about it! Here we have open Arctic Ocean with no ice, a lot of daylight hours, and a 10-fold increase in solar absorption. Now, you know where I am coming from!

To make matters worse, please know that in the above NASA site, the reduced visible ice in the “after” photo may be more than 40 percent less thick. What this means is the ice lost is even greater than the visual observation of the “before” and “after” photos presented.

Now, imagine the thickness did not change! So imagine the remaining ice in the “after” photo to be 40 percent less in total area. This would be the more accurate visual image to compare the summer ice decline. The site below provides evidence of the thinning taking place.

http://www.grida.no/climate/vital/30.htm

Since the absence of winter ice regeneration is accelerating, this means the positive feedback loop is the more dominant mechanism over arctic greenhouse gases since they have not changed that much in the last few years whereas more open ocean has. The summer-time effect is very strong lasting into the winter in ways which prevent large areas of open ocean from refreezing during the dark winter months. This fact suggests to me that any realistic emission reductions will not overpower this positive feedback loop.

I suppose it’s understandable that science gets divided into little departments, but it’s nevertheless surprising how rarely all the pieces get stuck together to make a big picture. I was shocked to hear (from a NASA climatologist) that the temperature predictions we read about come from models where the CO2 input is based on projections of human ghg emissions and that these models do not necessarily link to any carbon cycle models or take into account other positive feedback loops. Although this new research redresses the balance, It’s scary to hear that even these predictions are conservative. If I understand him correctly, Dr. Scheffer suggests these feedbacks could be even stronger not just because of the methane but also because of human degradation of our natural carbon sinks. As long as observed climate trends correspond to the worse-case end of the predictions, there is more work to do.

but on the subject of freak weather phenomena, a while back we were discussing the increasing frequency of Tornadoes in the UK. I recalled the story my sister told me of bales of straw and then a fish falling from the sky in Felixstowe, Suffolk as a possible result of being sucked up by a local tornado and a waterspout off the coast. It seems she was not the only person to have that experience on the East coast:

http://news.independent.co.uk/uk/this_britain/article570246.ece beste

Nuclear power and nuclear weapons require positive feedbacks to work – that says a lot for the fear which we should feel about what could happen in the very near future.

Feedbacks in the natural environment are naturally negative, in other words they tend towards balance, which is why the atmosphere does not turn into a Venusian hell…at the moment.

If we consider some of the feedbacks that may be coming our way, many people will feel like just packing up and getting on with life as normal, while others will be motivated to act immediately with sort of energy that this problem deserves:

- Increased carbon acidification breaks down the sea creatures that store carbon in their structures, releasing more carbon in the process.

- Increased temperatures melt Siberian permafrost causing matter to decompose, releasing methane and carbon dioxide.

- Loss of snow and ice on mountains decreases the albedo (reflectivity) of the land, causing more heat to be absorbed, causing more snow and ice to melt.

And so on.

An even bigger worry are the feedbacks and triggers that we don’t even know are in the extremely complex earth-sea-air systems. Anyone who understands chaos theory will by now have their heart in their mouth : the thresholds are waiting to be breached so we need to grab this problem and sort it out now!

The fact that the rate may be much quicker is terrifying.

It is well known that biological activity is increased in warmer climbs and is virtually non existant at the poles.

It is equally well known that Biological activity produces GHGs

Therefore warmer epochs should see increased biological activity and hence the observed historical rise in atmospheric CO2

Worth thinking about?

Here is further food for thought

Mann98, conclusion wrong?

Andrei, “well known” does not mean “there is clear scientific evidence”. How well known is this information?

Have a look at http://www.theglobaleducationproject.org/global-ecology.php : Phytoplankton density is greatly increased towards the poles and cold water currents, and without phytoplankton the greenhouse effect would move towards a runaway process – see http://www.planktos.com/educational/overview.htm#history for more information (“Phytoplankton are annually responsible for more of the planets total photosynthetic biomass than is plant life on land.”)

The contribution by animal respiration to CO2 is minimal compared to the absorption of CO2 by plankton and other plant life, the GHGs given off by our burning of hydrocarbons and our destruction of the plant life that absorbs the CO2. The only direct exception to the GHG balance here is due to flatulent cattle, required due to our increasing dependence on meat, releasing methane, which is 22 times more potent as a GHG than CO2.

So please think before you post, Andrei.

Andrei, I suggest you look at a good post on RealClimate which should answer your question.

The answer is very simple: People have a fairly good idea how much carbon is released by burning fossil fuels and destroying forests. They have calculated the amount of carbon released in the atmosphere every year. They compare that with what actually appears in the atmosphere – a great deal less. They have also measured how much the oceans absorb (by measuring acidification, I think). Again, if you add all the extra carbon in the oceans and all the extra carbon in the atmosphere together, it still isn’t nearly as much as the carbon we all pump into the air. This means that the biosphere must absorb more than we emit.

The worry of course is that this free service won’t continue for every longer – and even worse, that the rate of warming might one day harm the biosphere so much that it will start to decline and indeed become a net source of carbon.

I thought that the bbc one programme last night really showed that this is now not a fringe issue but one that is now at the fore front of peoples minds. Unfortunately the viewing figures for X-Factor on itv will be way higher than bbc. But still we need must see that the topic is no longer just about scaring and warning, it is now about doing. And the media is going to be the best way to influence real people. I like sport aid, it works brilliantly, and maybe it is time to start to think on those terms. Fund raising on a massive scale, to one raise awareness and two raise capital for the many programmes schemes that are struggling for funding.

just a thought