How representative?

While most of the Climategate disclosures concerned tree ring studies, one of the questions still to be answered is why so many of the emails selected for release were about SRES - the IPCC's estimates of how different things that affect the climate, including carbon dioxide, will vary in the future.

Now, via Richard Betts' Twitter feed comes news of the IPCC's latest version of these emissions scenarios, with a snazzy new name: the Representative Concentration Pathways. There is a paper describing how they were put together here.

I've only taken a quick glance, but I'm struck by how much carbon capture is predicted in some of the RCPs. Is this realistic? I thought CCS was something of an unproven technology.

IPCC on climate sensitivity

Nic Lewis, best known as one of the co-authors of the O'Donnell et al paper on Antarctic temperatures has a must-read post up at Judith Curry's place. The title tells you all you need to know:

The IPCC’s alteration of Forster & Gregory’s model-independent climate sensitivity results.

This is pretty shocking stuff.

Again.

Testing two degrees

One of the questions I would have liked to ask at the Cambridge conference the other week related to a graph shown by John Mitchell, the former chief scientist at the Met Office. Although Mitchell did not make a great deal of it, I thought it was interesting and perhaps significant.

Mitchell was discussing model verification and showed his graph as evidence that they were performing well. This is it:

Click to read more ...

Material World on climate models

The BBC's Material World programme interviewed Prof Paul Valdes, a climate modeller. The message appears to be that climate models are very bad at reconstructing major climate shifts in the geological record and are probably bad at predicting future ones too.

The conclusion of the interview appears to be that it's worse than we thought. This struck me as slightly odd given that the rest of the interview appeared to revolve around the fact that the models don't tell us anything very useful.

Eduardo Zorita has further thoughts at Klimazwiebel.

Material World excerpt

Zombie science - Josh 109

Obscure cinematic reference? Well yes, but then isn't that kind of appropriate?

More cartoons by Josh here

Climate video nasty

These videos of a conference run by the Newton Institute for Mathematical Sciences popped up on one of my Google alerts. There's a lot to see but it's all interesting stuff.

First up is a presentation by Tim Palmer, an Oxford climate modeller, who is particularly interesting on the large biases in climate models and the "misleading" way these are dealt with in "some reports".

Click to read more ...

Goot paper on consensus

Murray Goot of Macquarie University reviews papers on the scientific "consensus" on climate change. This is a reasonably balanced piece and not just because it mentions The Hockey Stick Illusion a couple of times.

In essence Goot's papers looks at the Oreskes and Anderegg papers as well as considering the polls of climatological opinion run by von Storch and Bray and concludes that there is a consensus that the majority of recent warming is down to CO2.

Click to read more ...

What we agree on

One of the interesting moments from the Cambridge conference was where Dr Eric Wolff of the British Antarctic Survey tried valiantly to find a measure of agreement between the two sides. I didn't get the details written down, but Dr Wolff has kindly recreated what he said at the time for me, for which many thanks are due.

In the table below, Dr Wolff's summary is in the left hand column and my comments are on the right. Blank implies broad agreement.

Click to read more ...

Antarctic fox

A response to Cox and Stockwell

Retired geophysicist Geoff Davies has responded to the Cox and Stockwell article (discussed here) about Hansen's new paper on climate model representation of ocean heat uptake and mixing. He accuses them of misrepresenting Hansen.

The article contains basic misrepresentations of Hansen and of the substance and implications of a draft paper by Hansen.

The Hansen paper does not weaken the case that humans are the main cause of global warming. On the contrary, it suggests we have unwittingly and temporarily shielded ourselves from the full effects of our activities.

I've only whizzed through both the Cox/Stockwell and the Davies articles, but I think the difference is over the credibility of Hansen's explanation. Hansen is saying that ocean heat uptake has been overestimated, and therefore the reason we haven't seen much warming is that we must have got aerosols wrong too, with the two errors effectively having balanced each other out. Cox and Stockwell are saying that maybe the effect of CO2 is not as strong as previously thought.

Is that right?

Hansen the hopeful - Josh 98

Scrutinising the models

There has been something of a flurry of posts around the sceptic blogosphere about climate models and I wonder if this may continue to be a theme in coming weeks after James Hansen's recent admission that climate models are getting ocean heat uptake and the mixing of heat in the ocean wildly wrong.

This story is covered in layman's terms here by Anthony Cox and David Stockwell:

The Earth’s energy balance is the most important measure of anthropogenic global warming [AGW] because it shows whether energy is leaving or accumulating.

Among 52 dense pages of science, Hansen reports on two experiments from the last eight years that call for major revisions to the GCMs.

This is definitely a "read the whole thing" kind of article.

Put alongside the poor performance of the models against observations in recent years do we really have a watertight scientific case that demands a policy response?

Non-linear system is linear

Only in climateland - Willis Eschenbach's post at WUWT is very interesting. He shows that the output of a major climate model is essentially just a lagged linear combination of its inputs. This is kind of odd when what they are modelling is a non-linear system.

Climate change just happens

I've always shuddered rather when people say things like "70% of the observed temperature change is due to manmade carbon dioxide emissions". Christofides and Koutsoiyannis clearly feel the same way as shown in their presentation to the EGU a few days ago.

...we should be careful when we talk about causes, and that trends and shifts do not necessarily imply non-stationarity or a change in forcings: they can just happen.

The implications for all those claims of "we can only reproduce climate history with carbon dioxide in our forcing mix" seem rather profound.

It's the ocean, stupid!

Jeff Id gave up blogging a few months back, but fortunately for us he just can't resist the urge to return from time to time. According to RP Snr, what he has said today is pretty important:

If you were to transfer enough ocean energy directly to the atmosphere to create 4 degrees of atmospheric warming, how much would that change the average temperature of the Earth’s water?

Would you believe –  0.001 Degrees C of ocean temp change?  The left side pancake wouldn’t look any different in Fig 1!   Hell, it wouldn’t change if we were in another oceanic current inspired ice age — think about that.