For the last couple of decades, though, there has been ample observational and empirical evidence to flesh out and validate the models.
Possibly you missed that part in your frantic searches for denial material.
You will find them in David Appell's article, an interesting one, which includes the more expansive piece:
But is the climate less sensitive to greenhouse gases like carbon dioxide and methane than has been forecast?
How Much of a Slowdown?
While there’s no doubt that the Earth’s recent surface temperature has not leaped ahead like it did in the 1980s and 1990s, it hasn’t exactly shown a flat trend over the last decade and a half.
Each of the three most-cited datasets estimating average surface temperature shows warming over the last 15 years (180 months): GISS: 0.11 C; HadCRUT4: 0.07 C; and NCDC 0.07 C (.2, .13, and .13 F respectively).
Like all measured numbers, these data have uncertainties, as discussed in the sidebar at the end of this article.
These increases are certainly less than the warming rates of the 1980s and first half of the 1990s of about 0.15 to 0.20 C (.27 and .36 F respectively) and per decade. The earlier period may have provided an unrealistic view of the global warming signal, says Kevin Trenberth, climate scientist with the National Center for Atmospheric Research in Boulder, Co.
“One of the things emerging from several lines is that the IPCC has not paid enough attention to natural variability, on several time scales,” he says, especially El Niños and La Niñas, the Pacific Ocean phenomena that are not yet captured by climate models, and the longer term Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) which have cycle lengths of about 60 years.
From about 1975, when global warming resumed sharply, until the 1997-98 El Niño, the PDO was in its positive, warm phase, and heat did not penetrate as deeply into the ocean. The PDO has since changed to its negative, cooler phase.
“It was a time when natural variability and global warming were going in the same direction, so it was much easier to find global warming,” Trenberth says. “Now the PDO has gone in the other direction, so some counter-effects are masking some of the global warming manifestations right at the surface.”
In a 2011 analysis, researchers Grant Foster and Stefan Rahmstorf tried to mathematically separate out the influences of El Niños and La Niñas, volcanic eruptions that can lead to cooling, and a recent decrease in the radiance of the Sun. They found that the surface has an underlying average warming trend of about 0.15 C (0.27 F) per decade, presumably resulting from greenhouse gases."
Climate change 'will make hundreds of millions homeless'
Robin McKie, science editor
The Observer, Saturday 11 May 2013
Climate change is amplifying risks from drought, floods, storm
and rising seas.
Photograph: Simon Maina/AFP
It is increasingly likely that hundreds of millions of people will be
displaced from their homelands in the near future as a result of global
warming. That is the stark warning of economist and climate change expert
Lord Stern following the news last week that concentrations of carbon
dioxide in our atmosphere had reached a level of 400 parts per million (ppm).
Massive movements of people are likely to occur over the rest of the
century because global temperatures are likely to rise to by up to 5C
because carbon dioxide levels have risen unabated for 50 years, said
Stern, who is head of the Grantham Research Institute on Climate Change.
"When temperatures rise to that level, we will have disrupted weather
patterns and spreading deserts," he said. "Hundreds of millions of people
will be forced to leave their homelands because their crops and animals
will have died. The trouble will come when they try to migrate into new
lands, however. That will bring them into armed conflict with people
already living there. Nor will it be an occasional occurrence. It could
become a permanent feature of life on Earth."
The news that atmospheric carbon dioxide levels have reached 400ppm has
been seized on by experts because that level brings the world close to
the point where it becomes inevitable that it will experience a catastrophic
rise in temperatures. Scientists have warned for decades of the danger of
allowing industrial outputs of carbon dioxide to rise unchecked.
Instead, these outputs have accelerated. In the 1960s, carbon dioxide
levels rose at a rate of 0.7ppm a year. Today, they rise at 2.1ppm, as
more nations become industrialised and increase outputs from their factories
and power plants. The last time the Earth's atmosphere had 400ppm carbon
dioxide, the Arctic was ice-free and sea levels were 40 metres higher.
The prospect of Earth returning to these climatic conditions is causing
major alarm. As temperatures rise, deserts will spread and life-sustaining
weather patterns such as the North Indian monsoon could be disrupted.
Agriculture could fail on a continent-wide basis and hundreds of millions
of people would be rendered homeless, triggering widespread conflict.
There are likely to be severe physical consequences for the planet. Rising
temperatures will shrink polar ice caps – the Arctic's is now at its lowest
since records began – and so reduce the amount of solar heat they reflect
back into space. Similarly, thawing of the permafrost lands of Alaska, Canada
and Russia could release even more greenhouse gases, including methane, and
further intensify global warming
To many people, the topic itself is boring.
Last edited by Earthling; 12th May 2013 at 09:57 AM.
A wonderfully illuminating story on climateaudit.
PAGES2K Online “Journal Club” « Climate Audit
With the hockey stick view of climate history effectively broken, the IPCC needed fresh meat to squeeze into their latest assessment report AR5 to keep up the ill supported claim that we have never seen climate behave as it has over the last 100 years.
To do that they needed a suitably placed PEER REVIEWED hockey stick publication they could cite.
Some will know of the PAGES2K paper. This was the vehicle for that manipulation. But things went wrong. It was rejected by Science and the cut off date for papers allowed to be included in AR5 was fast approaching .
What to do?
As luck would have it, Nature recognised in PAGES2K a special quality that would allow them to publish PAGES2K outside the normal practice of setting acceptance dates that would rule PAGES2K inelligable for inclusion in AR5. They simply had to classify PAGES2K as a "progress article" - a special class of paper reserved for work in fields "not sufficiently advanced to be subject to peer review". Kafkaesque I know to try and manufacture a peer reviewed article by claiming the work can not be peer reviewed, but hey this is climate science we are talking about.
So it was duly published with much fanfare, but it is by Nature's own policies. NOT a peer reviewed paper.
It is even funnier (or scandalous) when you point out that PAGES2K was actually a compendium of regional hockey stick temperature reconstructions and one of the , Gergis' study of Antarctica was itself rejected as a stand alone paper. But apparently bundled into PAGES2K it is solid science.
How can the science be settled when science is practiced in this way?
But you will notice Mcintyre is very careful not to say there is anything wrong with the science .... and indeed the paper has been out for a month or more, agrees with other publications and with no rejoinder or substantive scientific objection to its conclusions.
Willing to wound[McIntyre] I therefore am not moralizing about whether something was “amiss” in this case. However, I recommend that readers should not presume that the journal peer review constituted serious due diligence of the PAGES2K article.
But afraid to strike
Just hint a fault
and hesitate dislike.
(Alexander Pope, "Atticus")
Peer-review is the first round of quality control .... more happens after the paper is published. No paper is taken as "received science" unless it is replicated.
PS One would have to ask why someone like Steven McIntyre does no original research of his own ... he used to complain that the data was not available to him. But now it is ..... and the man has not done a tither of work on the evidence, just carp and whine about the work done by other people.
Potholer answers three questions :
(1) What is the evidence that CO2 causes global warming?
(2) What is the evidence that it has done so in the past?
(3) What is the evidence that it is doing so now?
He answers those questions without any reliance on computer models or the IPCC. Well worth the quarter hour if you regard yourself as "skeptical" about global warming, or even if you do not.