Global Warming

[ivor]

Here's an interesting side of the Global Warming debate.  It's a seventy-three minute video.  Some of the politics I disagree with.  The science of it was very interesting.

[Sibling Zono (anon1mat0)]

On the solar activity argument, the danish guy that has been working on it doesn't say that is one thing or the other but that the effect (of solar activity, cosmic rays and stratospheric clouds) should be included in the simulations. Although he claims that he has been pressured because of his opinion. OTOH, there is a very comprehensive article in the printed edition of Scientific American for anthropogenic global warming (the header of the article can be found here). The printed article says that it was considered.

The subject is a difficult one but there is a political agenda on both sides (although I would think that there are more economic interests on the 'everything is fine' side).

[ivor]

I've always been pro-global warming.  Is it true what they are saying about CO₂ lagging temperature by 800 years? 

[beagle]

Haven't checked out the video yet  but I've seen interesting stuff by Bjorn_Lomborg elsewhere.

Anything that has The Economist and Scientific American lining up on opposite sides is interesting IMHO, in that they're both intensely rational publications. Whatever the science I suspect that as The Economist implies, big science and environmental interests are going for the player rather than the ball.

As I understand it, one of the arguments is that spending money now on development is better than using it to fight global warming, in that developing economies are messy economies (and always have been).

On the opposite side of the argument is the car boom in China and India, and the possibility of mass starvation if (big if) climate change is already moving the monsoon time and latitude.

[Griffin NoName]

Unless we evolve to eat cars

Seems always to be an assumption that there is some point in "fighting" global warming. I suppose if at best we can delay it, or prolong it, we might preserve human life long enough to colonise space successfully. May be time to ask for an International Referendum on quantity over quality of life now.

[ivor]

If CO₂ lags temperature by 800 years then it seems the simple answer is CO₂ has nothing to do with global warming.   They point out in the video that water vapor is a much larger green house gas than CO₂.  That sounds reasonable to me.

Where did they get that graph on solar activity?

[Aggie]

If CO₂ lags temperature by 800 years then it seems the simple answer is CO₂ has nothing to do with global warming.   They point out in the video that water vapor is a much larger green house gas than CO₂.  That sounds reasonable to me.

Where did they get that graph on solar activity?

Water is a much more important GHG than CO₂ (in terms of spectral absorption)  - but it's also in physical equilibrium with surface water & ice, so it's a bit of a straw man. 

Actually, methane is 4x as powerful a GHG as CO₂, so there are arguments to be made for exploiting any resources which have the potential to be released (clathrates etc.).  Rotting vegetation flooded out by any new hydroelectric dam can release the GG gas equivalent of a fossil-fueled power station for the first 10 years or so of it's life - mind you, it's in-cycle carbon rather than 'old' sequestered carbon.

[ivor]

One volcanic eruption trumps all those right?  We don't see spikes in temperature because of those.

I am still interested in seeing that solar activity chart and comparing with a temperature chart.

Water is a much more important GHG than CO2 (in terms of spectral absorption)  - but it's also in physical equilibrium with surface water & ice, so it's a bit of a straw man.

Could you explain what that means in terms any idiot can understand? 

[Swatopluk]

If it gets warmer, more water evaporates, ice melts and exposes a dark surface that absorbs 90% radiation instead of reflecting 90%.
Water vapor absorbs radiation in a different part of the spectrum than CO₂. That certain substances act as GHGs and with different intensity is due to different absorption efficiency and their position in the spectrum. Potent greenhouse gases fill gaps that radiation usually escapes through. It is like blocking the safety valve of a steam boiler. Adding extra stuff where other substances already absorb makes a much smaller difference, as is the simple increase in concentration outside those gaps.
Volcanoes also emit aerosols that compensate partially for the increased CO₂ (cloud-cooling). There have been volcanic events in world history that had a tremendous effect on climate (e.g. the Dekkan volcanism).
That there is no simple connection T = f(c(CO₂)) is due to the nonlinearity of many coupled effects (positive and negative feedbacks).
A simple example that seems paradox is the behaviour of a continuous chemical reactor with external cooling. Under certain conditions the reactor will become unstable, overheat and explode, when the temperature of the cooling medium is lowered. If one looks at the balance equations it becomes clear, why but a layperson would usually not believe it without demonstration (the lab demonstration in the practical course is quite impressive).
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I thought methane was 20 times as effective as carbon dioxide, must check

[Aggie]

One volcanic eruption trumps all those right?  We don't see spikes in temperature because of those.

This is the thing - anthropogenic sources are relatively minor, but what is the effect in the long run?  Example:  A pack-a-day cigarette habit is a relatively minor cost compared to the sum total of housing, food, vehicle expenses etc, but if continued over a lifetime (and if the price of smokes keeps outpacing inflation, like it is up here), could have significant effect compared to if that money was instead rolled into a compounding interest investment.  I.E - even though the 'natural' amount is huge, adding consistently to that over time could make a measurable difference.

Water is a much more important GHG than CO2 (in terms of spectral absorption)  - but it's also in physical equilibrium with surface water & ice, so it's a bit of a straw man.

Could you explain what that means in terms any idiot can understand? 

OK - if we didn't have ANY greenhouse gases (GHG), this planet would be too damned cold. 
The  water in the atmosphere is the most important GHG and absorbs much more radiation than CO2 does, but it is continuously falling out as rain and evaporating back up, so there's little chance of increasing the net distribution of water (can be argued that more will evaporate as the temperature rises, but more clouds may help to reflect more incoming solar radiation, slowing down the warming process.  Water is a bit of a wild card).


IMO, all the political effort currently being put into this global warming debate should be put into making our energy use more efficient and environmentally friendly - there are many MANY other air pollution issues caused by the combustion of fossil fuels that are having measurable impacts on human health (especially in cities); also, if we can slow down fossil fuel consumption rates we'll be able to use this resource for longer.

Do agree a bit with the idea of putting effort into PROPERLY developing technologies in developing nations so that they grow up cleaner than the last generation - it's easier to build something right the first time as these are needed than to decommission an old nasty pollution-generator and rebuild an clean one as a replacement.

[Aggie]

I thought methane was 20 times as effective as carbon dioxide, must check

I may be wrong...  that was off the top of my head.  4x is either water or methane, I think, but methane has a half-life in the (oxygenated) atmosphere, so that may account for the lower number if it's a cradle-to-grave factor (i.e. it becomes CO2 eventually and loses the absorption advantage).

[ivor]

I totally agree on less pollution, more energy efficiency thing.  Our energy security is important.

The new R134A freon used in air conditioning is a terrible green house gas.

Does any body know where to get that solar activity graph?

[Sibling Zono (anon1mat0)]

There are a bunch in the wikipedia entry for Solar variation.

A 2006 study and review of existing literature, published in Nature, determined that there has been no net increase in solar brightness since the mid 1970s, and that changes in solar output within the past 400 years are unlikely to have played a major part in global warming. It should be stressed, the same report cautions that "Apart from solar brightness, more subtle influences on climate from cosmic rays or the Sun's ultraviolet radiation cannot be excluded, say the authors. However, these influences cannot be confirmed, they add, because physical models for such effects are still too poorly developed."

The danish guy I was talking about is Henrik Svensmark. Here is a link of the interview on Discover Magazine regarding global warming, solar activity and cosmic rays. Interestingly, the wiki's page on him mentions a study that challenges that theory.

Muddy waters...

[ivor]

Great article!

The basic idea is that solar activity can turn the cloudiness up and down, which has an effect on the warming or cooling of Earth's surface temperature. The key agents in this are cosmic rays, which are energetic particles coming from the interstellar media—they come from remnants of supernova explosions mainly. These energetic particles have to enter into what we call the heliosphere, which is the large volume of space that is dominated by our sun, through the solar wind, which is a plasma of electrons, atomic nuclei, and associated magnetic fields that are streaming nonstop from the sun. Cosmic-ray particles have to penetrate the sun's magnetic field. And if the sun and the solar wind are very active—as they are right now—they will not allow so many cosmic rays to reach Earth. Fewer cosmic rays mean fewer clouds will be formed, and so there will be a warmer Earth. If the sun and the solar wind are not so active, then more cosmic rays can come in. That means more clouds [reflecting away more sunlight] and a cooler Earth.

I remember years ago on a very cloudy day, I could see a spot on the sun as it was rising.  Very cool.

I think a lot of people are letting emotion get in the way of good science. 

I am all for conservation but I can't see forcing developing nations to use solar when we don't use it ourselves.

Here's some interesting stuff.



Sometimes they diverge.  I wonder, shouldn't the Earth's magnetic field have something to do with it too?  How about vulcanism?  Could that explain some of divergence?

[Sibling Zono (anon1mat0)]

I am all for conservation but I can't see forcing developing nations to use solar when we don't use it ourselves.

I am quite pessimistic to tell the truth. If the cause of the recent warming is anthropogenic it is impossible to moderate emissions in time before a significant change. According to the IPCC:

The previous IPCC assessment reported a warming trend of 0.6+/- 0.2 degree Celsius over the period 1901 to 2000. Because of the strong recent warming, the updated trend over 1906 to 2005 is now 0.74+/- 0.18 degree C.

IOW the temperature rose above the estimate of the previous IPCC report. According to the article we will experience further warming which could be ameliorated or worsen.

OTOH, if the science is wrong and the stuff that is making the current warming is not anthropogenic, we are simply adding more fuel to an ongoing fire and -more importantly- are royally screwed.

The 'beautiful' part of it is that it is quite hard to know what the short and medium term consequences are going to be. It could be stronger hurricanes, sea level rise, a significant change in global weather, or as someone else predicted, a significant change in sea currents and sea salinity that could even trigger a new ice age.

Whatever is going to happen doesn't look good from this end, and while perhaps is not going to affect us in the short term I do fear that my son and his children will experience the consequences.