From the Carnegie Institution – maybe we should build more cooling towers.
Washington, DC. — Scientists have long debated about the impact on global climate of water evaporated from vegetation. New research from Carnegie’s Global Ecology department concludes that evaporated water helps cool the earth as a whole, not just the local area of evaporation, demonstrating that evaporation of water from trees and lakes could have a cooling effect on the entire atmosphere. These findings, published September 14 in Environmental Research Letters, have major implications for land-use decision making.
Evaporative cooling is the process by which a local area is cooled by the energy used in the evaporation process, energy that would have otherwise heated the area’s surface. It is well known that the paving over of urban areas and the clearing of forests can contribute to local warming by decreasing local evaporative cooling, but it was not understood whether this decreased evaporation would also contribute to global warming.
The Earth has been getting warmer over at least the past several decades, primarily as a result of the emissions of carbon dioxide from the burning of coal, oil, and gas, as well as the clearing of forests. But because water vapor plays so many roles in the climate system, the global climate effects of changes in evaporation were not well understood.
The researchers even thought it was possible that evaporation could have a warming effect on global climate, because water vapor acts as a greenhouse gas in the atmosphere. Also, the energy taken up in evaporating water is released back into the environment when the water vapor condenses and returns to earth, mostly as rain. Globally, this cycle of evaporation and condensation moves energy around, but cannot create or destroy energy. So, evaporation cannot directly affect the global balance of energy on our planet.
The team led by George Ban-Weiss, formerly of Carnegie and currently at Lawrence Berkeley National Laboratory, included Carnegie’s Long Cao, Julia Pongratz and Ken Caldeira, as well as Govindasamy Bala of the Indian Institute of Science in Bangalore. Using a climate model, they found that increased evaporation actually had an overall cooling effect on the global climate.
Increased evaporation tends to cause clouds to form low in the atmosphere, which act to reflect the sun’s warming rays back out into space. This has a cooling influence.
“This shows us that the evaporation of water from trees and lakes in urban parks, like New York’s Central Park, not only help keep our cities cool, but also helps keep the whole planet cool,” Caldeira said. “Our research also shows that we need to improve our understanding of how our daily activities can drive changes in both local and global climate. That steam coming out of your tea-kettle may be helping to cool the Earth, but that cooling influence will be overwhelmed if that water was boiled by burning gas or coal.”
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@- Stephen Wilde says:
September 17, 2011 at 4:19 am
“Instead the claim is that when vapour condenses out there is a release of latent heat at the higher level which is instantly lost to space by radiation upwards.”
Then the claim is nonsense.
The condensation of the water vapor does not change the temperature of the atmosphere at that altitude, just reduces the rate of cooling with altitude – the difference between the dry and wet adiabatic lapse rates.
WHY is the latent heat of a body of air and cloud at a higher level going to be ” instantly lost to space by radiation upwards.” ??
Half that radiation from a mass colder than the surface will be towards the surface. But more significantly the lower temperature of the air/cloud mass at altitude will emit LESS energy than a warmer mass at the surface. By taking energy from the surface and transporting it into the boundary layer which is at a lower temperature than the surface it REDUCES the rate at which energy is lost from the surface and lower atmosphere.
That is why the sea surface at the equator never cools as much as a dry desert area at the equator at night, the loss of energy from the cooler sea surface and clouds above is less than from a hotter land surface with dry air above.
If an increase in the hydrological cycle because higher temperatures increase evaporation causes a negative feedback that reduces warming then at what level does this feedback stabilise the temperature? And why did it not stabilize it during past warming episodes (Eemian, Minoan, Roman, MWP) ?
“WHY is the latent heat of a body of air and cloud at a higher level going to be ” instantly lost to space by radiation upwards.” ??”
Simply because it is surrounded by very cold air molecules which absorb it and radiate it upwards. The higher a molecule is situated the more emitted radiation will go upward because the air above is much less dense and presents less of an obstacle to upward radiation than does the much denser air below the radiating molecule.
The fact is that the net flow is always upward and the higher the emitting molecule the more of the emitted energy goes upward.
The evaporation/condensation process gives a parcel of energy a head start in its exit from the system without it registering in terms of temperature at the surface. It is EXTRA energy ejected from the system over and above the energy radiated upward as a result of the sensible heat which does register in terms of temperature at the surface.
If you still don’t get it then you have a mental block that I cannot break.
As regards the Eemian etc the situation there would have been driven by a change in solar energy into the oceans which DOES alter surface temperatures but that is nothing to do with downward IR and indeed a change in the water cycle DID stabilise the warming by shifting the surfacve air pressure distribution poleward for a faster exit of energy from the system.
AGW theory would say that at such times there should have been runaway heating leading to catastrophe but it didn’t happen.
izen says:
September 17, 2011 at 7:03 am
“Half that radiation from a mass colder than the surface will be towards the surface.”
At that altitude the radiation emitted upward will not likely be absorbed by anything. Downwelling IR will be most likely absorbed on the way down due to the thickening atmosphere. Subsequent emissions, use same formula and you have the reverse of greenhouse effect and a flow of energy into space. Convection carries energy upward and by-passes the majority of greenouse gases. You are correct that it is not instant but it is a huge volume of energy carried aloft all day every day by all forms of convection. The entire atmosphere continually circulates upward and downward.
You appear to have it stuck in your head that heat is somehow attracted to the surface.
Stephen Wilde says:
September 17, 2011 at 12:03 am
phlogiston and izen.
I dealt with both your points upthread as follows:
“The energy value of the shortwave reflected is always greater than that of the longwave which is slowed down in its exit from the system. Shortwave reflected is lost to the system altogether but downward longwave cannot develop unless the shortwave enters the system first so less shortwave getting in also ultimately reduces downward longwave..”
This is of course a more complete analysis, to look at short and long wave components.
To simplify this discussion and avoid obfustication and distractions, one should focus on the radiation balance with respect to clouds without involving temperature. Dragging in temperature just mires the discussion intractably – this is perhaps the goal. Scientists do this a lot – particularly when the outcome of research has political interest implications – bring in impressive technical sounding arguments that complicate and bog down the discussion, but which are in fact irrelevant.
Someone made a very persuasive post recently (possibly david hoffer) that in studying satellite radiative balance data it would be much more precise to deal only with measured fluxes of radiation, rather than the current practice of trying to interpret temperatures from satellite measured radiation. However this makes the paucity of support for AGW much more clear cut. But bringing in attempts to model temperatures from satellite measurements brings i huge additional error and complexity, and mires the debate intractably.
In rugby this tactic is called collapsing the scrum.
Recently Bill Illis, in the threads on Spencer and Braswell, showed convincingly that if you compare cloud cover with outgoing global electromagnetic radiation, that cloud cover accounts for more of less 100% of variation in outgoing radiation, with R2 as high as 0.77.
SOLUTION TO CLIMATE CHANGE AND POWER CRISIS
(Reward NRs. 100,000/= One Lakh to First who can prove wrong) Dr. Dev Bahadur Dongol
(In The Rising Nepal: Overturning Global Warming; 25 June 2009 and Don’t Blame Gases For Green House Effect; 24 September 2009 and By Mark W. Hendrickson; Don’t Treat Co2 As A Pollutant, 25 June 2009)
What we know
a. Related to climate change – CLIMATE CHANGE DUE TO GASES IS IMPOSSIBLE: SOLUTION TO Climate Change
1. Green house is made using transparent solid materials – plastics or glasses. We cannot build a structure using fluids. So gases can’t form a green house, thus no GHE due to gases.
2. The higher the altitude our climatic atmosphere, troposphere, is colder.
3. At 30,000 feet Ozonosphere is minus 58 degree centigrade.
4. Heat transmission – always higher to lower temp. Heat reached upper region of the troposphere cannot come back to hotter places below.
5. Fluids (liquids and gases) by convection method of heat transmission deliver heat from hotter to colder zone. Thus air helps the earth to cool down. This process goes on all the time nonstop but the process is not good enough to cool down the sun heated earth as the gases carry least amount of heat.
6. Troposphere is a homogenous mixture of gases, not layered. As the air of the atmosphere is always moving up and down, to and fro, the freely moving molecules can’t be layered. Had it been layered co2 would be at the bottom of the atmosphere i.e. just above the earth’s surface. Then we are dead. We need o2 to be alive.
7. Air is a perfect transparent medium after space. It does not reflect light so we don’t see air. Opaque materials reflect light so we see them. If the air is opaque? We wouldn’t need eyes. So there is no way for gases in the higher altitude to send heat back.
8. Closed room gets heated uniformly but upper part is warmer as hot air goes up. So if GHE due to gases were possible our atmosphere would be hotter at higher altitude.
9. a. It becomes cold immediately when it rains. b. Annual frequency of rain is decreasing. Reduced frequency of nature’s effective cooling system, the rain cycle, is causing the ‘global warming’. Or, it could not be cooler as it would with more rain.
10. Rain cycle is related to heat and evaporation only and no other factors. Rain can occur without plants; though it lets water to go in the atmosphere by transpiration and hold water on earth by not allowing soil to dry quickly as surface without plants. Evaporation for regular rain cycle can’t be from sea, lakes or rivers (4 billion yrs on not warm enough) but from land surface. Why not more rain cycle nowadays? Warmer, sea surface area and temp increasing (favorable for evaporation)? Half portion of the earth is always exposed to the sun and they do not vary temp seasonally as land surface does daily. Human settlement is reducing evaporation from land areas by covering it with houses, roads, pavements etc; deserts, and deforestation etc. Evaporation of water can deliver maximum quantity of heat and reduce the temperature. So rain cycle needs new explanation.
11. Land surface changes temperature even on daily basis – hot during day time and cold during night (or seasonally as well) unlike sea or lakes or river water (they are almost consistent even in 4 billion years).
Thus global warming or climate change due to gases is impossible. No one has explained the reason nor can be explained scientifically. Instead of warming, gases are cooling the earth by convection method of heat transmission naturally and man has no control over the process.
Causes and solution: by keeping land surface areas always wet as used to be in old days, the evaporation of water will be consistent and thus rain cycle will be regular. It is an easy job for mankind now and it is possible only till we have snow on mountains. At the end of holy festival we always had rain (in the evening). Covering of land surface areas by human is reducing the evaporation. We are doing this mistake because we studied that rain cycle occurs from the evaporation of water from sea or lakes or rivers. Regular rain means colder weather, snow on mountains, rich vegetation/ balanced ecosystem, recharging ground water and eventually reducing sea water level. Climate change problems are all related to water or rain cycle. Without regular rain cycle problems related to water can’t be solved.
Conclusion: Thus it can be concluded that we have climate change because we are studying the process of rain cycle wrong way scientifically.
b. SOLUTION TO POWER CRISIS (we cannot blame water)
(New Ways to Harness Hydropower; The rising Nepal, 2009 March 14 and धेरै सस्तोमा जलविद्द्युत; गोरखापत्र, २३ जेष्ठ २०६६)
We can harness many times more hydropower from already installed hydropower installations by adding more turbines in series. The application of standing still water column to running water condition has been a blunder in hydropower engineering. At present we are harnessing minimum hydropower. In a standing still water column pressure effect of the water column varies according to the height. But in a running water column the pressure effect is uniform throughout the water column (Bernoulli Theory). Therefore by installing multiple turbines in series we can run all of them uniformly. (See demonstrations).
Demonstration: water meter is a miniature form of turbine. We can install many of them in series and run all of them uniformly. We use force of gravitation to run water in hydropower. So it is more appropriate to say g-power than say hydropower. We cannot reduce nor block nor shift force of gravitation; it is always there at a given point. The series connection of turbines is also applicable with thermal power-plants (fossil fuels or nuclear) as they use steam, a fluid to drive turbines.
Dr. Dev Bahadur Dongol email: dev.dangol@yahoo.co.uk Mobile-9841 647 393
Resi: 4 25 30 45 Shahid Shukra Galli, House no.24 Teku , Kathmandu – 12
Blog: devbahadurdongol.blogspot.com
Challenge to IPCC / UNFCCC, SHAME ON YOU
Solution to CC and Power crisis
Dear Dr. Pachauri and Mr. Algore,
Please give me either one scientific reason/ theory that justifies CC is due to gases OR STOP ACCUSING GASES for CC. Just accusation is not science. CC by gases is impossible. Please visit devbahadurdongol.blogspot.com for solutions to CC and ‘power crisis’. Summary is attached for your convenience. I have also explained the mistake being done in the hydropower engineering and, its correction can give us unlimited hydropower.
Challenger,
Dr. Dev