Originally Posted by andrejsv

I think the graphs is off, it seems to indicate that current temperatures are higher that at any time in the holocene and higher than at the medieval warm period, both are incorrect, please provide proof of that and correct the graph. It also shows temperatures slowly recovering from the little ice age.. that is not in dispute.

No evidence exists for your assertions on the holocene and the medieval warm period. No wonder you don't bother to present any. The balance of evidence is the other way. While the Medieval Warm Period saw unusually warm temperatures in some regions, globally the planet was cooler than current conditions.

Therefore your post is of no consequence.

Originally Posted by andrejsv

What?


Now why would you resort to accusing someone of being a holocaust denier?

Because he is one. Ask him.

If you are not aware of the crazy beliefs of most climate science deniers on the thread, then you have been extraordinarily blinkered. Certainly, too quick to point out the dust speck in other eyes.

There are Holocaust deniers, nicotine deniers, unabashed fascists, believers that the President of the United States is a Muslim communist from Kenya, greenhouse effect deniers, creationists, ... you name it.

You should take a serious look at the company you keep.

Whaddya know! There's hope for the US yet. Not all their young are brainwashed science deniers.

Originally Posted by owedtojoy

As far as I can tell, Richard Lindzen thinks climate is like the performance of the Irish Rugby team ... an excellent performance (against Australia) is followed soon afterwards by a cr*p one (against Wales), so nothing changes much over time. He says things like "Temperature is always rising or falling", implying that he believes the climate is stationary over the long term i.e. in the long run it always stays the same and there is no trend.

He has no evidence for this, and there is significant evidence for the reverse proposition .. that climate at the moment has a long-term, warming trend. Deniers admit this when pushed into a corner ... they will agree with the ~1C rise since 1850, but try to dismiss it with handwaving and shrugs.

I showed this a week or so ago, and it is a bit impressionistic, but it is still a very good picture to understand what is going on, despite it naive inclusion of a "medieval warm period". Yes, there was a MWP in the North Atlantic, but there is scant evidence it was a worldwide phenomenon.

I mean, it's only logical that a 40% rise of the greenhouse gas CO2 must conclude in global warming. You don't need to be a scientist to realise that. Remarkable is also that climate change deniers are not only denying science, they're also immune to common sense.

Satellites find over 500 billion tons of land ice melting worldwide every year, headlines focus on Himalayas

Well. 500 billion tons are equivalent to 500 cubic kilometres. That would cover Ireland with more than 20 feet of ice.

Barry Bickmore tears to shreds the amateurish graph published by the Wall Street Journal 16.

So before I go on, let me be blunt about these guys. They know about error bars. They know that it’s meaningless, in a “noisy” system like global climate, to compare projected long-term trends to just a few years of data. And yet, they did. Why? I’ll let you decide.

Because the error bars would look something like this:



RealClimate: Bickmore on the WSJ response

If we take a look at the Global Ocean Heat Content the picture is even clearer.



What happens if you heat a glass with water and ice cubes, say with a hair dryer? Well. First the ice melts. Then the water heats up. So what can we expect when summer ice will be gone in the Arctic, possibly by 2030?

Originally Posted by SirCharles

Satellites find over 500 billion tons of land ice melting worldwide every year, headlines focus on Himalayas

Well. 500 billion tons are equivalent to 500 cubic kilometres. That would cover Ireland with more than 20 feet of ice.

Annual melting of 500 billion cubic kilometres of ice would let our oceans rise by 1.4 mm per year. Expansion due to rising temperatures is adding to current sea level rise (currently 3.3 mm per year).

Originally Posted by imokyrok

Whaddya know! There's hope for the US yet. Not all their young are brainwashed science deniers.

Amazing. What a slick production too. all their own words and thoughts. I am so impressed with the critical thinking skills being honed in schools in America. Certainly no regurgitation of official truths there.

John Nielsen-Gammon (Texas State climatologist) has a great post on his site tacking the old "CO2 is plant food" meme. The expectation here is that as CO2 in the atmosphere increases, plants will flourish and become more abundant. Forget for the moment, as climate science deniers hope you do, that most plants are considered weeds when it comes to growing foodstuffs.



Downer for climate science deniers. Carbon dioxide assimilation is non linear so that at about 450ppm (which the atmosphere will reach quite soon), carbon assimilation starts to saturate and level out. In other words, the biosphere as a "sink" for carbon becomes nullified.

Notice how the net assimilation vs. ambient CO2 concentration curve trails off towards a flat response above about 500 ppm. The shape of the curve is very similar between the leaves, while one assimilates more efficiently than the other. I included two lines to represent the approximate slope of the curve in the region 300-600 ppm ambient CO2. Both lines show a much lower than double increase of assimilation for the prescribed doubling of CO2 (note that current CO2 levels are nearing 400 ppm, while preindustrial levels were just below 300 ppm), and the higher CO2 becomes, the lower that slope.

This means that even if all plants on earth showed this particular response, it is not efficient in removing the extra atmospheric CO2 provided, and becoming less and less efficient the more CO2 is offered, facts conveniently omitted by people who want to mislead.

Worse:

So [limitations on soil on water] further reduces the biosphere’s ability to uptake CO2-carbon in response to increasing ambient CO2 concentrations. Only in situations, where there are little to no other limitations on growth, such as in modern industrial agriculture providing irrigation and fertilization, does increased ambient CO2 unfold its full potential to spurt plant growth.

Roughly as a result of the above, the IPCC concluded, cited by John, that plant yields will increase somewhere between 0-25% (10-25% for C3 plants) when doubling CO2. There will be large geographical and species-related differences, with well-nurtured woody plants representing the high end number.

Guest Post: Carbon Dioxide and Plants | Climate Abyss | a Chron.com blog

And, finally and ominously,

At some point in the future, depending on factors including the absolute amount and rate of warming, as well as the plant growth response itself (aka how much extra carbon has come in), the terrestrial biosphere as a whole will become a net source to the atmosphere again.

The scientific debate is about when that will be (mid century? end century? next century?), not if. So while the IPCC (and John) is right, in the long term the message is more of a mixed bag, and this is likely going to be reflected better in the next IPCC report.