Global Shadowing?

[gan_nair]

First off, hello to all, I am new here, obviously. I am in no way a scientist and not many things about science interest me enough to study it. However I am interested in the environment and would like to know more about it, which is why I am here. Anyhow, here is my question.

 

I was talking to someone about global warming and the recent studies found on it. Before I go on I must say that the guy I was talking to is basically like me in the science scene. Anyways he told me somewhere he found this deal called global shadowing, and said that while global warming is bad and will worsen throughout the future, global shadowing will actually slow it down and possibly prevent it from doing as much damage as many think it will.

 

From what he told me, global shadowing is supposed to be how the gases we put into the atmosphere actually "shadow" the earth from the sun, which if they werent there, global warming would speed up and would due to the sea level raise, basically it would flood the world. I was wondering if there is any truth to this. And also, doesnt the water on the earth dissolve anyways? If so wouldnt that actually help out when the ice melts?

 

Again I am not a scientist and I dont really study the environment, if I just happen to be curious about a certain thing about the environment, I will read up on it. Or ask someone that actually knows what they are talking about. Thanks for reading and sorry if my questions seem stupid.

[Pangloss]

Hi, welcome to the board.

 

I've seen documentaries on this. My memory is hazy but I'll be happy to try and spur some further discussion on this (I'm sure someone will appear quickly to correct my many errors!).

 

If memory serves, the general idea is that certain dynamics have acted to retard the overall effect of global warming. Amongst GW critics this is seen as excuse-making, along the lines of explaining why more significant warming hasn't taken place. But the science of it appears (at least to my untrained eye) to be very real.

 

One example of this is the study that was done on contrails following 9/11. If memory serves, a scientist studied the change in albedo (reflectivity of the surface) due to the lack of airplanes flying during the 100% ground-stop that took place in this country following the terrorist attacks. Supposedly the study showed that contrails were a more serious problem than previously known.

 

The interesting thing about contrails is that they would presumably act to *cool* the Earth's surface. In other words, they're contrary to the warming trend. So the general idea is that they may be causing global warming to proceed less rapidly than other indications suggest that it should be proceeding at.

 

If that makes any sense at all. And again, my memory on this is sketchy; I'm just trying to further some discussion on it.

[john5746]

I think the discussion concerning global warming has changed from "if" to how bad and what to do about it. There probably are variables that scientists are unaware of or are difficult to take into consideration. The article below mentions that the melting of the ice sheets in Greenland and Antartica are not taken into account in the Intergovernmental Panel on Climate Change to be released Friday.

 

http://www.skiracing.com/index.php?option=com_content&task=view&id=4739&Itemid=2

[bascule]

You're talking about global dimming. This is the result of various reflective aerosols:

 

http://en.wikipedia.org/wiki/Global_dimming

 

Climate change attribution has been researched heavily. The latest research shows carbon dioxide having a significantly greater effect than dimming due to reflective aerosols:

 

 

Your friend was guessing. Science says otherwise. Notice the volcanic and sulfate forcings (both of which contribute to global dimming) have a negative temperature anomaly. Also notice that the effect of carbon dioxide is substantially greater than either of these forcings.

[1veedo]

Yeah, I think you're talking about global dimming. The irony is that global dimming has actually caused scientists to make conservative estimates about the temperature.

 

While you're saying "global shadowing" might slow down the effects of global warming, the opposite is actually true. Because we've cut back on aerosol emissions, temperatures might rise even more then what was previously thought.

 

Before anyone suggests we reverse global warming by causing more global dimming, let me point out that this has already been suggested and has been found to impractical. It would be nice to let everyone use aerosol, and even create factories with the sole purpose of pumping this stuff out in the atmosphere, but it's bad for humans and there are other unwanted environmental effects.

[gan_nair]

Thanks for the replies, although at first they seemed a little hard to catch what it was being said, 1veedo said it best for me to understand. So basically global warming is irreversable? And either way it will just keep getting worse as the years go on? Wow that sucks, maybe oneday someone will figure out the solution to it all. Thanks again for the replies.

[john5746]

Thanks for the replies, although at first they seemed a little hard to catch what it was being said, 1veedo said it best for me to understand. So basically global warming is irreversable? And either way it will just keep getting worse as the years go on? Wow that sucks, maybe oneday someone will figure out the solution to it all. Thanks again for the replies.

 

No, I think the idea is that it can be reversed or at least drastically reduced, if we reduce emissions and try to encourage absorption now. That is what all the fuss is about. We must admit there is a problem and that we might be the cause. Then take action.

 

The Earth will regulate itself eventually, of course part of that regulation may be the end of the human race or a large chunk of it.

[Royston]

I'm sure most of you guys have heard that the IPCC have released the first of four reports on climate change (six year study.) The lights of the Eiffel tower were switched off for five minutes to mark the occasion. In the UK, climate change due to anthropegenic sources, will now be included in the curriculum as compulsory.

 

It's just a matter of the world leaders enforcing measures to tackle the problem of carbon emissions...I'm hoping over this year that the global warming issue will come to a head, and finally, something will be done.

 

Please take a look at the BBC article below...

 

http://news.bbc.co.uk/1/hi/sci/tech/6321351.stm

 

Sorry if this is a little off topic...not specifically global dimming, but an important step nevertheless.