Interview Matt Ridley bij FD Energie Pro

Het FD heeft een nieuw online product opgezet, FD Energie Pro. De site is net online gegaan en vooralsnog is de content gratis te lezen. Karel Beckman van de Energy Post heeft als interim hoofdredacteur de eerste verhalen uitgezet. Hij vroeg mij of ik er als freelancer voor wilde schrijven en het toeval wilde dat ik een dag later Matt Ridley zou opzoeken op diens landgoed ten noorden van Newcastle. Beckman wilde graag een interview met hem en zodoende staat dit interview nu als een van de eerste verhalen online. Het verhaal is nu nog gratis integraal te lezen. Hier de intro:

Viscount Matt Ridley is politicus, auteur, journalist, klimaatcriticus, bioloog, natuurliefhebber, ex-bankier, en eigenaar van een steenkolenmijn. Maar hij is bovenal: rationeel optimist. Hij gelooft dat de mensheid dankzij steeds verdere specialisatie en handel een welvarende toekomst tegemoet kan zien. Daarbij is een efficënte energievoorziening onmisbaar – en die kan volgens Ridley niet komen van bronnen als windenergie en biomassa. Journalist Marcel Crok bezocht Matt Ridley op zijn landgoed in Noord-Engeland.

 

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Matt Ridley: opwarming van de aarde is goed voor de wereld

Matt Ridley heeft een interessant stuk geschreven voor de Spectator getiteld Why climate change is good for the world. Het leunt sterk op het werk van Richard Tol en sluit daarom prima aan bij het vorige blogbericht van Tol zelf.

Zoals de titel al zegt geeft Ridley een opsomming van positieve effecten van de toename aan CO2 en opwarming van het klimaat:

The chief benefits of global warming include: fewer winter deaths; lower energy costs; better agricultural yields; probably fewer droughts; maybe richer biodiversity. It is a little-known fact that winter deaths exceed summer deaths — not just in countries like Britain but also those with very warm summers, including Greece. Both Britain and Greece see mortality rates rise by 18 per cent each winter. Especially cold winters cause a rise in heart failures far greater than the rise in deaths during heatwaves.

Over de effecten van CO2 schrijft hij:

The greatest benefit from climate change comes not from temperature change but from carbon dioxide itself. It is not pollution, but the raw material from which plants make carbohydrates and thence proteins and fats. As it is an extremely rare trace gas in the air — less than 0.04 per cent of the air on average — plants struggle to absorb enough of it. On a windless, sunny day, a field of corn can suck half the carbon dioxide out of the air. Commercial greenhouse operators therefore pump carbon dioxide into their greenhouses to raise plant growth rates.

The increase in average carbon dioxide levels over the past century, from 0.03 per cent to 0.04 per cent of the air, has had a measurable impact on plant growth rates. It is responsible for a startling change in the amount of greenery on the planet. As Dr Ranga Myneni of Boston University has documented, using three decades of satellite data, 31 per cent of the global vegetated area of the planet has become greener and just 3 per cent has become less green. This translates into a 14 per cent increase in productivity of ecosystems and has been observed in all vegetation types.

Dr Randall Donohue and colleagues of the CSIRO Land and Water department in Australia also analysed satellite data and found greening to be clearly attributable in part to the carbon dioxide fertilisation effect. Greening is especially pronounced in dry areas like the Sahel region of Africa, where satellites show a big increase in green vegetation since the 1970s.

Het is goed dat Ridley dit onderwerp aansnijdt. De positieve effecten van CO2 en opwarming zijn te lang vrijwel onbespreekbaar geweest en blijven zoals Ridley aangeeft onderbelicht in IPCC-rapporten. Met de lagere schattingen voor klimaatgevoeligheid op basis van waarnemingen is deze discussie alleen maar actueler aan het worden.

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Nic Lewis’ response will hit the Met Office like a boomerang

Nic Lewis has published a lengthy and quite technical response on a recent Met Office report, see the posts at Bishop Hill and Judith Curry. His response will hit the Met Office like a boomerang.

Boomerang
Why like a boomerang? In July the Met Office published three reports about the ‘pause’. In the third and I would say most important one they looked at the implications of the pause for estimates of climate sensitivity and projections of future warming. Their key conclusions were (see their concluding remarks):

Despite the fact that the first decade of the 21st century has been a period during which there was very little global mean surface temperature rise, the range of TCR [Transient Climate Response, MC] estimates from the CMIP5 models lies within the TCR derived from observations, including this period.

When projections from the newer CMIP5 models are combined with observations, and specifically including the surface temperatures from the last 10 years, the upper bound of projections of warming are slightly reduced, but the lower bound is largely unchanged. More importantly, the most likely warming is reduced by only 10%, indicating that the warming that we might previously have expected by 2050 would be delayed by only a few years.

In simpler words, Met Office claims the recent pause in global warming has had little impact on estimates of climate sensitivity and future warming and models and observations largely agree with eachother. Met Office backed this up with several figures. Below I show their figure 5, showing estimates for Equilibrium Climate Sensitivity (ECS), which is the warming due to a doubling of the CO2 concentration, after the system has reached a new equilibrium.

Met Office figure 5

Otto et al is a recently published study that estimated climate sensitivity from observations. Visually the message is clear: there is a huge overlap between Otto et al (observations), CMIP3 and CMIP5 (the models) and palaeo estimates. Models therefore are ‘consistent with’ the observations, which is important to have faith in their projections of future climate. Nic Lewis was a coauthor of the Otto et al paper together with a large group of lead authors of the upcoming AR5 report. Lewis wrote the response in a personal capacity.

Now to make a long introduction short, here is Lewis’ adjusted version of the Met Office figure 5:

Lewis added other recent estimates of ECS based on observations (Aldrin, Lewis, Masters), he removed the palaeo estimates (as these are far too uncertain and contain “little information”) and he used flasks to show the 5-95% range of the distribution. The black bars are Lewis’ best estimates (medians). The white bars are the Met Office best estimates, for CMIP3 and 5 Met Office used the means instead of the medians.

The “boomerang” is the red bar on top of the CMIP5 distribution. This is the ECS of Met Office’s own flagship HadGEM2-ES model. As one can clearly see Met Office’s own model is not only far more sensitive than the observations suggest but even more sensitive than all other models. As Lewis put it:

And HadGEM2-ES has an ECS that exceeds not only the 95% bound from Otto et al but also that from two other recent observationally-based studies. Moreover, both the TCR and the ECS of HadGEM2-ES exceed the 95% bounds derived not only from CMIP3 models but also from CMIP5 models other than HadGEM2-ES.

So the Met Office model’s best estimate lies outside the range of both the observations and all the other models. It is a clear outlier. Met Office failed to disclose this in their own report, only showing the range of all the models in their figure 5 (and in other figures).

Relevance for the upcoming AR5 report
Although Lewis’ response is directed at the Met Office report, his piece is also highly relevant for the upcoming AR5 report. In an article today in the Wall Street Journal Matt Ridley quotes from the leaked SPM of AR5 (my bold):

Specifically, the draft report says that “equilibrium climate sensitivity” (ECS)—eventual warming induced by a doubling of carbon dioxide in the atmosphere, which takes hundreds of years to occur—is “extremely likely” to be above 1 degree Celsius (1.8 degrees Fahrenheit), “likely” to be above 1.5 degrees Celsius (2.4 degrees Fahrenheit) and “very likely” to be below 6 degrees Celsius (10.8 Fahrenheit). In 2007, the IPPC said it was “likely” to be above 2 degrees Celsius and “very likely” to be above 1.5 degrees, with no upper limit. Since “extremely” and “very” have specific and different statistical meanings here, comparison is difficult.

Still, the downward movement since 2007 is clear, especially at the bottom of the “likely” range. The most probable value (3 degrees Celsius last time) is for some reason not stated this time.

Apparently IPCC is planning (countries will negotiate about the final text in Stockholm later this month) to lower its likely lower bound for ECS from 2.0 in AR4 to 1.5 in AR5. By doing this the median estimates based on observations shown in the Lewis’ figure above fall into the likely range. So this rightly reflects the recent literature.

However, less assuring is that Ridley reports that in the draft SPM “The most probable value (3 degrees Celsius last time) is for some reason not stated this time”. As can be seen clearly in the Lewis’ figure, all the recent most probable values based on observations lie between 1.5 and 2. The central estimate of the models is 3. Or as Lewis put it into his conclusions:

Observationally-based median estimates for TCR and ECS are often comparable to the bottom of model-based uncertainty ranges.

This means that only the least sensitive models come close to the observations. Now this generates a big dilemma for the IPCC authors which could explain why so far – in their draft SPM – they failed to mention a best estimate for ECS. Recently there has been is a growing discrepancy between observationally based estimates and model based estimates for ECS. Should IPCC give equal weight to both methods? Should IPCC average the central estimates of both methods (leading to a reduced new estimate of let’s say 2.5)? Or should they put most weight onto the observations? In the last case they should lower their best estimate to at least 2. That would be a spectacular result as the best estimates for ECS hardly changed at all since the 1979 Charney report.

I hope many countries (including my own) will urge the IPCC to publish a best estimate for ECS (like they did in AR4) or – in case not – to clearly explain why they decided not to mention it this time. I see this as one of the most if not the most important decision for the four day meeting in Stockholm. On 27 September we will know the answer.

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Afkoeling aerosolen echt kleiner

In mijn boek De staat van het klimaat schreef ik dat research sinds het vierde IPCC-rapport erop wees dat het afkoelende effect van aerosolen (aanzienlijk) kleiner is dan tot nu toe gedacht. Op pagina 118 staat:

Terwijl het opwarmende effect van roet dus op het lijstje opwarmende factoren moet, lijkt het afkoelende effect van aerosolen almaar kleiner te worden. Dat wil zeggen, kleiner dan de balken in afbeelding 8 suggereren. In 2009 publiceerde de Noor Gunnar Myhre een artikel in Science, waarin hij de koeling door het directe aerosoleffect naar beneden bijstelde.

Het indirecte aerosoleffect lijkt ondertussen helemaal op de helling te staan. De Amerikaanse klimaatonderzoeker Graeme Stephens van Colorado State University is nauw betrokken bij twee belangrijke satellietmissies van NASA: CloudSat en Calipso. Deze twee satellieten vliegen vlak achter elkaar aan en geven een ongekend scherp driedimensionaal beeld van wolken en aerosolen. Uit de metingen blijkt volgens Stephens dat het indirecte aerosoleffect vrijwel nul is.

Vooral de zeer lage schatting voor het indirecte aerosol effect (het effect van aerosolen op wolken) van Stephens baarde opzien. Stephens vertelde mij dat tijdens een interview dat ik met hem had in de zomer van 2009 in Fort Collins. Hij vertelde het bovendien in een Gewex-lezing in 2009, zie deze blog van Pielke. De onderzoekers van PBL en KNMI die mijn boek doorlichtten vroegen zelfs bij Stephens na of hij dat inderdaad gezegd had. Lees verder…

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