Global Dimming

[Guest lightnix]

I've already made this post in a couple of other forums. It may not be the usual Blue Room fare, but it's got me worried...

 

I just got around to watching the video I recorded of last week's Horizon, on the subject of Global Dimming. Although I've become a little suspicious of falling journalistic standards on the program (especially since they teamed up with the Discovery Channel) I must say that it was one of the most frightening pieces of TV I've ever seen.

 

The story so far...

 

In the 1980s, three groups of scientists independently discovered evidence that less sunlight was reaching the Earth than twenty years previously; in fact as much as 20% less in some areas. Initially their findings were ignored, as they conflicted with the predicted effects of Global Warming. However, as further evidence was uncovered in meterological records across the world, the results were gradually accepted and the phenomenon was given its name.

 

Then the hunt for the cause began and, unsurprisingly, it turned out to be air pollution. Not the Greenhouse Gases, but the particles of dirt, soot, sulphur dioxide and the like, which spew out of our factories and exhaust pipes. When these get into clouds, water condenses around them (into raindrops) more rapidly than it would in unpolluted clouds. One effect of this is to make the clouds shinier, so that more sunlight is reflected back into space. Then there are aircraft contrails, which spread out and reflect even more sunshine away from the Earth. More about contrails in a moment...

 

It is now believed that Global Dimming has already been responsible for climatic disasters around the world, including the Ethiopian droughts of the 70s and 80s which led to Band Aid. If Global Dimming is allowed to continue unchecked, further, similar disasters will occur. The "good" news is that since Europe (especially) has begun to reduce this kind of pollution, the effects of Global Dimming seem to be starting to diminish.

 

BUT...

 

Because Global Dimming is such a newly discovered phenomenon, its effects have not been accounted for in the computer models used to predict climate change, to the point where these models are now pretty well useless.

 

Back to the contrails... For the three days following the 9/11 attacks, all internal and US bound commercial flights were grounded and the American sky was briefly a contrail-free zone. An Americam climatologist decided to use this opportunity to gather data for his work on Global Dimming and in those three days recorded an average increase in temperature across the USA of 1°C.

 

Just think about that for a second: A 1°C rise, in only 3 days, simply by removing aircraft contrails from the equation.

 

It seems that Global Dimming has been masking the true effects of Global Warming for some time and that the latter is much stronger than previously imagined. If we cut the pollution causing Global Dimming without doing something about Greenhouse Gases, then Global Warming will accelerate more rapidly than anyone has previously imagined, even in their wildest nightmares.

 

If these phenomena continue to run unchecked, the Earth could see temperatures rise by as much as 10°C in as little as a century. This would turn temperate countries like the UK into deserts and render desert areas like the Sahara totally uninhabitable. After a 4°C rise, plant life will start to die. Once it is dead and dried out, it will most likely catch fire, releasing further millions of tons of CO2 into the air. Once temperatures have risen by 10°C, billions of tons of methane locked up in the oceans as hydrates will dissolve out and break free into the atmosphere. The greenhouse effect produced by methane is eight times stronger than that produced by CO2.

 

The bottom line is that we have just twenty-five years to do something concrete. At the current rates of change, by the time we get to 2030, the point of no return will be reached and there will be absolutely nothing we can do.

 

Twenty five years... quite possibly within my own lifetime and certainly within those of many members.

 

I'm scared :P :)

 

Can we all drop our Grand Masters by 10%, please. Every little will help.

[bruce]

Back to the contrails... For the three days following the 9/11 attacks, all internal and US bound commercial flights were grounded and the American sky was briefly a contrail-free zone.  An Americam climatologist decided to use this opportunity to gather data for his work on Global Dimming and in those three days recorded an average increase in temperature across the USA of 1°C.

 

Just think about that for a second: A 1°C rise, in only 3 days, simply by removing aircraft contrails from the equation.

 

<{POST_SNAPBACK}>

 

Is a 3-day sample statistically significant? Wouldn't a more reasonable explanation be that during those 3 days, the US was suffering from "a bit of nice weather"?

 

 

The storms we had last week were the worst we have had for 40 years. The harbingers of doom immediately start going on about global warming, and how it was never like this in the past, when I were a lad....

 

Well, it WAS like this. or worse! 40 years ago! That's why these are the worst storms for 40 years or whatever....

 

Bruce.

[Modge]

I saw said program live and they felt it wasn't freak wheather because whilst as you so rightly say 3 days of decent weather happens, normally warm days == warm nights (I am aware that clouds keep the heat in but the program makers seemed to ignor ethier because they knew there had been the same cloud as usal or just "because"). In the case of these 3 days the tempurature rnage also expand so as the nights were colder also. and apprantly the temp range increase was well out of normal bounds, seasonal or otherwise.

[SceneMaster]

Guys, this sort of subject drives me nuts, considering I am doing GCSE geography and this is all my class discuss, no argue!!!

 

Yes global warming is a massive issue and there is a lot being done about it although not enough… Global dimming issue doesn’t help either as we are trying to clean up our atmosphere yet this is making global warming worse… ok there are loads of views out there whether global warming is actually happening and if it is it our fault… I would post a link to an essay I wrote on the different view points of the issue global warming but I am not allowed as it is currently one of my coursework pieces being submitted…

 

Basically don’t worry about global warming if it is going to happen then it has already started but we can reduce the effects… what we need to do is recycle, be more energy efficient and stop polluting (well particles umm… open to debate!!! But defiantly Co2 and the so called greenhouse gases) anyway regardless to save this planet from all the other problems such as waste problems, and the lack of energy resources which will soon find us in (coal and oil ect…)… and “if†global warming exists and is a problem then this will solve it as well… but basically regardless how much people go on about global warming there is not sufficient evidence to prove whether is exists or it doesn’t … I am personally undecided but take all evidence into account (I had to for my course) but I agree we should be doing all the necessary steps to prevent or stop global warming as we will benefit in so many other ways apart from stopping/reducing the phenomenon of global warming if it exists…

[Guest lightnix]

Is a 3-day sample statistically significant? Wouldn't a more reasonable explanation be that during those 3 days, the US was suffering from "a bit of nice weather"?

 

The storms we had last week were the worst we have had for 40 years. The harbingers of doom immediately start going on about global warming, and how it was never like this in the past, when I were a lad....

 

Well, it WAS like this. or worse! 40 years ago! That's why these are the worst storms for 40 years or whatever....

 

Bruce.

<{POST_SNAPBACK}>

 

It would certainly be foolish to base an entire theory on just one set of measurements, but the data recorded over that three day period forms just a tiny part of a large and growing body of evidence which supports this theory. Not just evidence which has been uncovered retrospectively by digging through the records, but measurements which have been taken since GD was first recognised.

 

OK, I'll admit now that I didn't get it quite right in my first post. As Modge correctly pointed out, what actually changed by 1°C over those three days was the range of temperature. Even so, my reporting error makes no difference to the fact that while an increase in this measurement had been expected, the magnitude of that change over such a short scale of time was unprecedented.

 

Sorry, bruce, but I believe that the mass of actual evidence which has been gathered from around the World in support of Global Dimming, far outweighs the speculation that it might just have been down to a bit of unusually nice weather in New York. There are too many other pointers.

 

Apart from that, are you really prepared to take a gamble on the future, on the basis of just one piece of speculation? What empirical data do you have to contradict that gathered by teams of professional scientists? OK, there's may be a possibility that they are wrong, but can we afford to take that chance?

[Guest lightnix]

I don't know if anybody else read it, but the headline story in this morning's Independent said that, according to a new report prepared by international government agencies, the point of no return for global warning could be even closer than the Horizon programme suggested, maybe less than ten years.

 

According to current predictions, global temperatures will rise by 2°C above pre Industrial Revolution levels (AD 1750) when the amount of CO2 in the atmosphere reaches 400 parts per million. As mentioned, at that point the Greenland ice sheet will begin to melt and will mark the beginning of the end.

 

Current CO2 levels are at 379ppm and rising by around 2ppm per year :P

 

Now please - drop your levels.

[P. Funk]

Had this post in mind at the panto on saturday - made sure I switched to workers as soon after the show as possible!

 

its scary :P

[Just Some Bloke]

Interesting that in another thread, on how things will be in 10 years' time, Peter speculates that:

 

Power consumption in theatres will be minute compared to todays draw.

 

Sounds like that may be a very good thing in many ways!

[paulears]

Er, what's this tree hugger stuff doing in a tech chat forum guys?

 

I appreciate the content, and respect everyones right to opinions - but this isn't the place (especially as the original post mentioned it had been posted to loads of forums.

[Guest lightnix]

I posted it across a variety of forums (four including this one) to see how the response would vary from one to the other.

 

I posted it in here because the various shows and productions staged across the world burn massive amounts of electricity and create a lot of waste without actually producing very much (other than a nice warm glow inside). How many megawatts of power are incinerated across the West End and Broadway on a nightly basis? How many tons of CO2 gets added to the atmosphere each year as a result ? How much of PVC do we collectively peel off our shoes and casually chuck into the environment every year?

 

Paul, how can you write this off as merely "tree hugger stuff" when it's on the agenda at the next G8 conference? Why is this forum "not the place" to discuss something which will affect the future of every single one of us ?

 

The report highlighted by The Independent was not produced by a bunch of wild-eyed crusties, it was produced by the National Research Council in the US; a member of the National Academies, a serously heavyweight body of scientists and academics.

 

Levels of CO2 and Methane in the atmosphere are higher today than at any time in the last 400,000 years and I'm afraid that sticking your head up your :huh: rse and pretending it isn't happening is no longer an option, if your grandchildren are to have any kind of future :P

[the kid]

Interesting that in another thread, on how things will be in 10 years' time, Peter speculates that:

 

Power consumption in theatres will be minute compared to todays draw.

 

Sounds like that may be a very good thing in many ways!

<{POST_SNAPBACK}>

 

 

Well if you think it is true, LED's need hardly any power at all, and there the new age of light.

 

12v lighting is already coming in to homes but not on a massive scale - if the power companys really wanted to help then they would actively encourage people to use the 12v halogen/LED system.

 

As many people will know all MNC's are only in it for the money, changing the countrys system to 12v or a lower once at least would be a mammoth task, so we could have a system like in america - have 110v mains and 240v cookers, but this will mean that we all pay less meaning that the power companys get less, and we can't have that can we? :)

[Andrew C]

12v lighting is already coming in to homes but not on a massive scale - if the power companys really wanted to help then they would actively encourage people to use the 12v halogen/LED system. 

<{POST_SNAPBACK}>

 

Energy efficient lighting is now a requirement of the Building Regulations. It's not retrospective, but any new-build or conversion must have the lighting designed to consume no more than 40W per fitting, including dimming and control gear. That means no BC or ES base holders, lots of compact fluorescent and some 12V systems.