I find the unprecedented melting of the northern polar cap the most convincing argument for a warming of the earth, at least of the northern hemisphere.

But there have been so many different reports and studies - it seems that the majority is in favour of global warming, despite some counter-evidence.

So I wouldn’t take single studies as pro- or counter-argument, but the whole picture has to be taken into account. And this picture seems to point into one direction.

But Julien the models say it should be continueous heating, at the moment that is not happeneing. How can we explain that?

There is no doubt that it is warmer now then 20 years ago (hence melting of the polar ice caps) but it has stopped for now.

But you are basing your insight on one report, right? I am not a climate expert, but I had the impression that there were reports clearly showing that the average heating was going on.

But I don’t care actually.

I don’t mind climate change, I rather mind overuse of limited resources, destruction of natural habitats, and the rapid pollution of our environment, some of which overlaps with concerns regarding climate change.

Theres more then one report. A number of scientists are mentioned in the report and they are all wroking independently.

The avergae heating is going on in the long-term sense, but temperatures have yet to go above 1998 level,s

I agree with the second part. Some people seem to link them a lot more then others. This is where I get confused.

“Global warming” might be real, but it might not. But here’s a question I’d like someone to answer: If the planet is warming, what temperature is it warming up from?

Sorry to interrupt, but I must add again: global cooling was predicted by astronomers decades ago. Every 2 centuries a solar minimum comes (so called Suess cycle). The last one was Dalton minimum around 1800 A.D.(read Ivanka Charvatova).

In 2050 the temperatures may be lower or the same as today. So we have plenty of time to think twice, before we leap. It is no “tcktcktck - time is running out, hurry.”

There is a recent post on the Real Climate blog dealing with the question of whether there is a warming pause. 1998 is the warmest year on record in data from the Hadley Centre in the UK, but according to NASA’s data, 2005 is. One difference between the two is that the coverage of the Hadley Centre has some gaps over the Arctic.

I think the article by Hudson fails to weigh up the facts properly. See my response if you’re interested: http://climatechange.thinkaboutit.eu/think2/post/the_devil_is_in_the_detail/

@Eamonn, Good question!!! Where is the starting point? 1970? 1990? or some other year?

@Vitezslav, Im not sure about the solar theory. Its a bit vague on the details and nothing is really supporting it. The oceans I can see and understand.

@Nanne, thanks for that! Slighty more confused now as its very technical, but I think I get it…

@Jodi, interesting stuff there!! I didnt realise the rest of it. But still that dosent fit the models which shows a continuing climbing of temperature. BUt I get your point.

@ Stephen Spillane:

a) “Nothing si really supporting the solar theory?” What?...Around 1500, 1650 (Maunder minimum) and 1800 we had lowered temperatures and solar activity was also low. Is this “nothing”? I would call it a proof. And from the past experience, I judge the futue.

b) Oceans and ocean cycles are a fine thing. But what triggers the changes? The oceans hardly change without a cause. The solar cause.

Hi, Stephen!

If you were investigating climate change between 1990 and 1995, you might think that the facts did not support the global warming hypothesis. Average global temperatures actually fell in that period.

Years, even decades, might show a drop in average temperature (like 1990-1995) or temporary stabilisation (like now) but it is the long-term trend in global temperature averages that scientists are looking at. That is what is going up.

As for the solar hypothesis, that’s a separate issue. The BBC article points out that studies seem to have disproven it. More importantly - what’s the mechanism? HOW does the sun change temperatures on Earth? It’s not as simple as energy in = temperature on Earth. If that was the case, then the Earth would have an average of -18 degrees. It actually has an average of +15 degrees - because of the greenhouse effect (and because of carbon dioxide). So adding more CO2 is a problem.

To put it another way - look at a graph of global temperature averages. The average temperature will be a jagged line going up and down.

However, if you plot the average path of that jagged line you will get a smooth line going upwards.

The BBC article is talking about the jagged line going up and down. The IPCC is talking about the smooth line going upwards.

So, in a face-off between the jagged line and the smooth line, which one should we pick? Or should we just toss a coin?

@Joe:

The solar mechanism in a nutshell.

1) Solar energy varies by approximately 0.1% between sunspot cycles. This has a small direct effect on radiative forcing.

2) Cosmic radiation striking earth is inversely proportional to the intensity of solar energy. Emerging science suggests that cosmic radiation plays a role in cloud seeding, which has an effect on the planet’s albedo.

3) A change of just 1% in cloudiness would have as much supposed effect as a doubling of atmospheric CO2.

4) When the sun is more radiant, less cosmic radiation reaches the Earth, cloud residence time decreases, lowering the planet’s albedo. Warming ensues.

5) When the sun is less radiant, more cosmic radiation reaches the Earth, cloud residence time increases, raising the planet’s albedo. Cooling ensues.

6) Solar radiation accumulates in the oceans over years, decades and centuries. This heat is circulated in the ocean and is released in unpredictable ways, triggering cooling and warming events. A larger incidence of heat release from oceans results in net warming.

7) Oceans have 1000 times the heat capacity of the atmosphere. A warmer atmosphere does not heat oceans, nor melt ice. Oceans have warmed, warming up the atmosphere along with it. The origin of this heat energy is from solar and deep ocean geothermal heat accumulation.

8) Solar origins of warming has one major advantage over CO2 origins of warming. Causation.

I could go on, but have run out of time.

@Joe Litobarski> You say “More importantly - what’s the mechanism? HOW does the sun change temperatures on Earth”... Are you joking? You do not believe, that Sun emits heat???

The influence on CO2 on climate is clearly weak. We have seen long periods, when CO2 was up, though temperatures were down. 130 000 B.C., 1940s-1970s or after 1998.

The theory about strong forcing of CO2 has been disproved by reality.

Both the smooth line and the jagged line say the same thing - so you can pick either. The “raw data” is the same in both.

Both a graph of average global temperatures year-by-year (jagged line) and a graph plotting the average temperature trend of those individual yearly averages (smooth line) show a long-term trend towards increasing temperatures. The smooth line hasn’t “made it up.”

Joe, I agree. We cannot make dire judgments based on ten years of data.

So how is it possible that IPCC makes a tremendous conclusion just based on ten years in the 22nd sunspot cycle, when there was low correlation between the sun( which did not go up compared to the 21st cycle) and the Earth temperatures (rising). All IPCC science based on ten years of a single sunspot cycle!!

Now it is our turn to make dire predictions on one decade.

Vitezslav, that’s a great point you make. Anyone who dared question the IPCC was called a “denialist”, which is some quarters is akin to being an apostate or a racist. But the shoe is on the other foot now, and it looks like the IPCC and its most dogmatic followers have overplayed their hand. And right before Copenhagen as well. Talk of bad timing!

@Vitezslav Kremlik

“Are you joking? You do not believe, that Sun emits heat???”

Hehe - No, you have not understood me!

Energy input from the sun is not enough. Energy input does NOT equal global average temperature. There is a substantial difference. This is why the average temperature of Earth’s moon is -18 degrees and the average temperature of Earth is +15 degrees - despite the fact they are the same distance from the sun.

Mike understands this, and is suggesting that the Earth’s oceans account for that difference.

Or the difference is because the moon lacks an atmosphere, and so has no greenhouse gasses, whilst the Earth does have an atmosphere and so the greenhouse effect plays a part.

@Mike

So you’re saying that it’s the ocean which retains heat from the sun, is that right? Do you believe that the greenhouse effect and CO2 plays no part?

Yes, oceans accumulate heat from the sun.

The greenhouse effect plays a very important part, keeping us 33 degrees warmer at the surface than we otherwise would be.

However, CO2 levels in the atmosphere are mostly saturated. The first 20% does most of what CO2 does. It absorbs all radiation available to it within 10 metres at the surface. This radiation is converted to heat and carried away by convection and conduction. A small part is re-radiated at a wavelength too low for greenhouse gases to absorb and escapes into space. Radiation, you see, is the limiting factor, not the gases which absorb it. Doubling CO2 would only half the distance until all radiation is absorbed. Halving 10 metres to 5 metres does not warm the planet. Even if all CO2 were absent, we wouldn’t observe significant cooling of the planet. CO2 only absorbs 8% of the Earth’s blackbody radiation, which overlap with other gases, most importantly, water.

In the absence of CO2, water would absorb the radiation instead. Water varies from 0-4% of the atmosphere at any given point, on a day-to-day basis. Water also carries latent heat from evapouration high into the atmosphere. Water also forms clouds that both insulate heat and reflect sunlight back into space at different altitudes. Water vapour is 5 million times a greenhouse gas than CO2 is. CO2 does almost nothing by comparison.

“...small part is re-radiated at a wavelength too long for greenhouse gases to absorb and escapes into space.”

Fixed.

@ Joe… I do not know how exactly Sun affects Earth temperatures. But I studied history so I am just concluding from the “past experience”, that Sun DOES HAVE effect, no matter how. Maunder solar minimum = lower Earth temperatures. 20th century increase from 30 to 75 sunspots annually = global warming…

It is just like evolution. We do not know exactly how it works, we are unable to immitate it, but we know, THAT it works. Somehow.

Hi Vitezslav,

I have to disagree with you on your last point. Evolution IS understood. We do know how it works, and we are able to recreate it in a lab (with fruit flies, for example).

We’ve even mapped the human genome!

It turns out that the BBC article might have got it completely wrong, though. The 2000s might be the hottest decade ever.

@Joe, again, for a thousandth time in these discussions, I must point out that you people are confusing things.

The first decade of the 21st century surely IS the hottest since 1900. Because we HAD a warming and the temperatures had gone up.

But between 2000 and 2010 the temperatures were NOT RISING any more. So it is erroneus saying that “warming is getting faster and faster and we must act fast”

@Vitezslav - “But between 2000 and 2010 the temperatures were NOT RISING any more.”

It looks like that might not actually be true, though.

http://www.cru.uea.ac.uk/cru/info/warming/

From 2000 to 2005, temperatures have risen. 1998 was so hot that it’s possible to say that temperatures have “fallen” since 1998, but that would be misreading the data.

2008 was cooler, but still the 10th hottest on record.

@ Joe. Surely, if you decide to ignore year 1998, you can say, that the temperatures have risen. Because if you decide to ignore data, you can say anything.

Vitezslav Kremlik: Mike understands this. Sure he does he so insightful, and you can be so to if you’d take the extra time and read more on

http://nov55.com/

apart from the excellent article on global warming it has a great article on Atheism, maybe it can cure you. But your atheism might come from the fact that you are an historian and not a scientist.

@Alexey: There is only one single valid argument “for God”. This is the “finely tuned Universe argument”. But using Everett’s Many Worlds Theory we can explain even this without a god. So, as Laplace said, God is a perfetly possible, but useless hypothesis.

So apparently I am not judging God just as a historian. I am judging him mainly by the “double slit experiments”.

I prefer to think about peak oil which is very hard to pass!
A lot of publication say that is is a terrible interrogation!