Global Dimming/Horizon

[malfunction]

Also - another small fact from here:

http://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)

1.74 × 10^16 J — total energy from the Sun that hits the Earth in one second

[daverobev]

Nobody is denying climate changes gradually over thousands of years.

What he is getting at is net change over the entire USA, not one small part. Obviously if a bank of cloud is sitting over New York it stops heat getting in during the day, and stops it getting out at night, so the temperature will be a lot more stable over that 24 hours than if its clear, where loads of heat comes in, then is radiated off at night. That much is obvious.

But if you take the whole of the USA, a VAST area, and average it all out..thats what he's saying - 5000 weather stations! And then for the three days where there ARE no planes about, the delta rises by a degree, and thats not happened in thirty years of records...coincidence?

If you look at evap rates over 100 years they are saying, not 10 or 20! And it links in with their being many more sooty airbourne particles, created by us.

[daverobev]

Also - another small fact from here:

http://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)

1.74 × 10^16 J — total energy from the Sun that hits the Earth in one second

I would assume that is hitting the Earth not the surface of the Earth - ie does not take into account reflected energy.

[Auran]

At first glance this is another one of those things that makes you think - "Oh my god we're doomed". But as you look into it there are still so many unanswered questions because we still don't fully understand the whole global picture. Yes we can hypothesise that if we sort out global dimming that the increased sun energy will cause runaway global warming - but what about the its effect on the Atlantic Conveyor? If that shuts down we'll be living in virtually arctic conditions in the UK.

Now personally I didn't see the BBC program but I did read the transcript and as usual it was high on emotional content and low on real science. I know that the BBC has to cater to a wide audience - but some science would be nice. What is worse is the degree to which everything is presented as carte blanche "This is the truth and all you'll ever need to know on this subject". Still, I'm probably a bit sensitive on this subject having studied the philosophy, ethics and role of science in society in a great deal of detail. Thus one of my bugbears is scientists (and I use the term loosely in their case) using the news media and other dodgy methods to get funding. Stealing it away from more intellectually worthy projects.

malfunction - pan evaporation tests are a scientifically valid method, as they are done under strictly controlled conditions; apologies if you were being sarcastic ;-)

[camarillo]

Why are any of you bothered by it? Everyone in this lifetime will be long dead before anything happens to the planet that would change lives in any way.

[malfunction]

Nobody is denying climate changes gradually over thousands of years.

What he is getting at is net change over the entire USA, not one small part. Obviously if a bank of cloud is sitting over New York it stops heat getting in during the day, and stops it getting out at night, so the temperature will be a lot more stable over that 24 hours than if its clear, where loads of heat comes in, then is radiated off at night. That much is obvious.

But if you take the whole of the USA, a VAST area, and average it all out..thats what he's saying - 5000 weather stations! And then for the three days where there ARE no planes about, the delta rises by a degree, and thats not happened in thirty years of records...coincidence?

If you look at evap rates over 100 years they are saying, not 10 or 20! And it links in with their being many more sooty airbourne particles, created by us.

So you take a lot of measurements that could all be easily swayed by essentially random events (clouds over new york as your say) and suddenly they all become relevant just because you average them out? Sorry but statistically speaking that doesn't make sense - you can analyse long term trends maybe but a 3 day 'abnormal' situation in 30 years - it's bad science AND bad statistics IMO.

[malfunction]

malfunction - pan evaporation tests are a scientifically valid method, as they are done under strictly controlled conditions; apologies if you were being sarcastic ;-)

I stand corrected. It still sounds cranky though (and yes I was being a bit sarcastic / OTT about it as it all sounds a bit tabloid / sensationalist)

[Byatt]

it's bad science AND bad statistics IMO.

good statistics is surely an oxymoron

[Rave]

My personal opinion is that I'm not hugely worried by climate change- I'm worried about the effect on the western economies of a reduction in the availability of oil (and hence a vast increase in the price). I'm keen to look into greater use of renewable energy- in fact I just this week went and dug out my old Electrical Engineering textbook to look into the possibility of building a 'scrapheap challenge' style wind turbine generator in my mum's garden. Anyway:

If we're worried about the reduction in energy from the sun being reflected back into space, then all we need to do is wonder outside with all the mirros in our houses and lie them on the ground to beam the energy back where it came from. Admittedly piloting planes by eye would become a bit more fraught, but they all have autopilot now anyway.....

Rich :¬)

[daverobev]

Its not bad science at all. If you take readings from 5000 stations each and every day, add the highest temperatures up, add the lowest temperatures up, subtract the lowest from the highest and divide by 5000, you get the average temperature range across those 5000 stations.

Now, if you chart that value...or rather chart the change in that value, and over thirty years it is always less than 1 degree difference. Then one day a madman flies planes into the World Trade Center in New York and no planes fly, so there's no vapour trails over the US. For those three days where there are no planes, the temperature difference is greater than a degree...then it goes back to "normal".

HOW is that bad statistics? You have seen vapour trails, they cover the sky. They showed a satellite picture of all the vapour trails - it covered the sky!

Something happened, and that lead to something else happening. Look at it from the other way. Something changed - a set of readings that had been stable for 30 years suddenly spiked. What was different when that happened? There were no planes flying.

Seems reasonably logical to me, considering the amount of planes that fly over the US, that them NOT flying would allow more sunlight down to Earth...

[icehot]

well we all know the US are the biggest consumers of oil in the world, lets just blame them

[malfunction]

Its not bad science at all. If you take readings from 5000 stations each and every day, add the highest temperatures up, add the lowest temperatures up, subtract the lowest from the highest and divide by 5000, you get the average temperature range across those 5000 stations.

Now, if you chart that value...or rather chart the change in that value, and over thirty years it is always less than 1 degree difference. Then one day a madman flies planes into the World Trade Center in New York and no planes fly, so there's no vapour trails over the US. For those three days where there are no planes, the temperature difference is greater than a degree...then it goes back to "normal".

HOW is that bad statistics? You have seen vapour trails, they cover the sky. They showed a satellite picture of all the vapour trails - it covered the sky!

Something happened, and that lead to something else happening. Look at it from the other way. Something changed - a set of readings that had been stable for 30 years suddenly spiked. What was different when that happened? There were no planes flying.

Seems reasonably logical to me, considering the amount of planes that fly over the US, that them NOT flying would allow more sunlight down to Earth...

It's bad science because it is being preached as the truth when it is in fact a coincedence. ONE of the things that was different for those three days was the fact that no planes were flying. And please do not tell me that the entire of the US was covered by vapour trails. Yes it's a big place and they fly a lot but that's just bloody stupid. I am not saying the vapour trails don't reflect the heat but it's not proven by any stretch of the imagination that the net effect of the planes not flying for 3 days caused the 1 degree change in some statistic - and I say again - averaging lots of things out does not always make it more significant, useful for analysing long term trends but a 3 day 'blip' would be discounted by anyone - it could have been down to LOTS of reasons. What I am also saying - and this is really trying to get back to why this thread annoyed me in the first place - is that no-one can say that "global warming would be catastrophic if it wasn't for all this polution / these vapour trails". That is NOT the scientific truth. Nor does it matter really - no one KNOWS why global warming is happening, and IMO the world is not coming to an end and we won't all have to live in boats or at the top of the mountains because the ice caps are melting.

[Auran]

Its not bad science at all. If you take readings from 5000 stations each and every day, add the highest temperatures up, add the lowest temperatures up, subtract the lowest from the highest and divide by 5000, you get the average temperature range across those 5000 stations.

Now, if you chart that value...or rather chart the change in that value, and over thirty years it is always less than 1 degree difference. Then one day a madman flies planes into the World Trade Center in New York and no planes fly, so there's no vapour trails over the US. For those three days where there are no planes, the temperature difference is greater than a degree...then it goes back to "normal".

HOW is that bad statistics? You have seen vapour trails, they cover the sky. They showed a satellite picture of all the vapour trails - it covered the sky!

Something happened, and that lead to something else happening. Look at it from the other way. Something changed - a set of readings that had been stable for 30 years suddenly spiked. What was different when that happened? There were no planes flying.

Seems reasonably logical to me, considering the amount of planes that fly over the US, that them NOT flying would allow more sunlight down to Earth...

Here's a thought..... all the people who would have been flying around in planes sat at home and used their air conditioning, or drove their cars, had barbeques..... or one of a myriad of other things that puts out heat enerygy

Yes there probably is a link, but not to the extent that he is trying to make, still he's probably coming up to another funding round

[daverobev]

Its like the whole "Peak Oil" thing...oil production is a bell shaped curve, we might already be over the tip meaning production costs will rocket while output will fall, while demand is increasing (China, for example)...but nobody seems to care.

IMO, we have a lot to answer for..."we" meaning the industrial nations/first world. There's two ways of looking at it...oh dear everything is gonna die, we need to do something...or we'll be ok, someone clever will think of something and we'll be fine.

Problem is...well its like the whole "don't leave your house, you could get hit by a bus!" thing. We might be fine. But who says so? What is so unbelievable about our cosy western life being turned upside down? Put council takes up by 15%?!? They can't do that! Kill x million people in Africa because we can't be arsed not to buy cheap crap in plastic packaging? Umm...well those Doritos look nice....

Personally I don't know what to believe. And I AM a scientist. I think a lot of stuff over here is going in the right direction, but I think the US has catching up to do. But none of that means we won't hit a point of no return and all die, horribly.

I think we need SOMETHING to happen to wake up our conscience..no not our conscience, our sense of preservation. Even getting solar panels and whatnot (which costs loads of oil to produce, by the way!).

malfunction, I can see what you mean about the program being dumbed down somewhat...but I don't think that means its complete nonsense. I think there is a lot more going on out there, but personally I don't think we can afford to be complacent in our beliefs that, without doing something ourselves, we'll all be okay...

[malfunction]

Oh no! Not peak oil again...

The problem is for me - any probably others - is that it all seems a bit like the FUD that the western governments are peddling to get our support on the war on terror, etc.

I do obviously know that oil and other fossil fuels are a finite resource and that there's the potential for the the world to get a little more 'interesting' when everything starts to dry up. And as a race, nation, etc we are not really preparing for the eventuality. But to be honest most people that talk about peak oil, etc sound like they're expecting the apocalypse. And well... It's just not going to happen like that IMO. The oil companies aren't going to keep producing oil at the same rate until they suddenly say... "Ooops! That's it! We're all out" supply will decline, things will get more expensive and life will probably have to change in some ways maybe - I know there are lots of things made out of oil - not just fuel - but we will find alternatives... Why? Because we have to - it's that simple really - and we will do it BEFORE it runs out (but probably not until oil becomes the most expensive way of doing / making it). It's going to be a gradual process and for my 2p worrying about it - really worrying about it - is about as sensible as worrying about a meteor hitting the earth and destroying mankind.

Edit: Just to expand on the above there is no way as far as I know to make these resources last forever. We could (and should) be more responsible with them but unfortunately that's not really the way of the world - they will continue to be consumed up to the point where it's no longer cost effective... I don't think there's anything you or I could do about it. It's like the war in Iraq... How many people were against that? How many people (rightly in my opinion) still believe that we've been lied to all along and that any 'inquiry' has at best been a joke? Has it make one bit of difference?

On the other stuff - there's no doubt that the human race is both stupid and selfish in many ways - lots of evils in the world and not lots of people doing anything about it cuz they either don't care or are too involved in their own lives. From the little I know the US are definitely behind in terms of consumption and pollution. But again things will eventually change - people are SLOWLY becoming more aware of the issues, governments are VERY SLOWLY forcing people and industry to be more responsible - I'm certain better progress could be made - but things are changing slowly in at least some parts of the world.

[Rcb]

Never been to Cov on a saturday night then?

Haha, I have actually