Feedbacks in Climate Science and Keynesian Economics

Warren Meyer posts of a parallel between Climate Science and Keynesian Economics. I posted about a subject close to his heart, and central to Keynesianism – Feedbacks. I have also attempted to update on the current debate on feedbacks.


There is a parallel between Keynes and the CAGW that is close to your heart – feedbacks. Pure Keynesianism is that an increase in government expenditure at less than full employment would have a positive feedback response. Keynes called the feedback measure the multiplier. (The multiplier is the reciprocal of the proportion of Government expenditure to GDP. So if government expenditure was 20% of GDP, then a $1bn fiscal boost would increase output by $5bn.)

By the 1950’s the leading sceptic was Milton Friedman who, in his 1962 book “Capitalism and Freedom”, estimated empirically that the multiplier was about 1 – that is it did not have any impact. Friedman was denounced as a denier and a dinosaur. (At the same time, mainstream economics adapted his verificationist methodology.) Indeed by the end of the 1960s it was generally agreed that the long-term feedback impact of government demand management was negative, as increased government expenditure crowded out the private sector, caused escalating inflation (as economic actors ceased to be fooled by the false signals 0f increased expenditure), slowed economic growth and generally undermined the very structures of the capitalist system. (see Friedman’s Nobel Prize lecture “Inflation and Unemployment“)

Keynesian thinking is that the capitalist economic system is inherently unstable. Stability is only achieved through the guiding hand of government. Keynes contrasted this with a caricature of neoclassical economics, with the macroeconomic system would rapidly come back into equilibrium. Similarly, the climate models assumption of chronic instability is contrasted by an extreme caricature of those who disagree with them. That is the “deniers” are saying that the climate is incredibly stable, with human beings having no influence. In both cases the consequence of this caricaturing is to automatically claim any extreme occurrence as vindification of their perspective.

Climate Change Impacts – UNIPCC and the Skeptics

Climate feedbacks are crucial to climate change forecasts. As Richard Lindzen1 said in his congressional testimony last year

  1. A doubling of CO2, by itself, contributes only about 1C to greenhouse warming. All models project more warming, because, within models, there are positive feedbacks from water vapor and clouds, and these feedbacks are considered by the IPCC to be uncertain.
  2. If one assumes all warming over the past century is due to anthropogenic greenhouse forcing, then the derived sensitivity of the climate to a doubling of CO2 is less than 1C. The higher sensitivity of existing models is made consistent with observed warming by invoking unknown additional negative forcings from aerosols and solar variability as arbitrary adjustments.

As Roy Spencer has recently claimed2,

In fact, NO ONE HAS YET FOUND A WAY WITH OBSERVATIONAL DATA TO TEST CLIMATE MODEL SENSITIVITY. This means we have no idea which of the climate models projections are more likely to come true.

Warren Meyer3 comments that

70-80% or more of the warming in catastrophic warming forecasts comes from feedback, not CO2 acting.

The impact is worse than that. It is not predicted temperature rise that is important. It is the catastrophic consequences that follow. These rise exponentially with temperature, so without the feedbacks more than 95% of the catastrophe does not happen. This is illustrated by the Climate Impacts table on page 10 of the UNIPCC Summary for policy makers4, where most of the impacts dramatically – almost exponentially – increase with temperature.

To illustrate this simply, the consequences of global warming will create costs. The reduced water availability, or crop failures will lead to increased hunger and in the extreme lead to deaths. The costs could also include the loss of species, both plant and animal.

To illustrate this graphically, plotting temperature increase against climate change costs, gives a Climate Change Impact curve as illustrated below.

There is no scale. There is no firm forecast of how high temperatures could go. The Stern review (Page 12) even saw fit to include a study with an upper estimate of 17.1oC maximum increase, and the UNIPCC AR4 has outlier estimates of 10oC. Neither do we know the costs. However, without the feedbacks, there is a temperature increase of around 1oC and so no hardly any noticeable costs. It is the pink line CCIS (S for skeptic) below.



  1. Quoted by Warren Meyer at

  2. Roy Spencer on 28th January 2011
  4. UNIPCC Summary for Policy Makers (SPM) reached from

Cure Worse Than The Problem? – Global Warming and California Prop 21 Compared

Warren Meyer seems to have got a little confused on his blog posting on Judith Curry’s ostracism by the alarmist community. He states

I find it just staggering that Judith Curry, whose hypotheses about man-made global warming probably overlap those of the hard core alarmists by 80-90%, can no longer be tolerated by alarmists.  Much as the Catholic Church radicalized Martin Luther when all he initially wanted to do was reform some practices (many of which the Church later reformed), the attacks on Curry seem to be having a similar effect.

The typical response by politicians, of course, is to try to get more money from taxpayers.  California has a ballot initiative this November proposing to raise vehicle licensing fees to all its citizens in order to fund state parks.  Unfortunately, this kind of funds earmarking by ballot initiative is already threatening to bankrupt California.  One problem with this approach is that it demolishes accountability — once an unelected state agency gets dedicated funds the legislature can’t touch, there is nothing that taxpayers can do if these funds are not spent wisely short of another time-consuming ballot initiative to revoke them.

In the case of state parks, the accountability problem is even worse, as the initiatives replace park user fees, which at least enforce accountability in that users can stop visiting if park services are not up to expectations, with a no-strings-attached bureaucratic windfall.  Compounding the problem, in many states the parks organizations report to rubber-stamp boards rather than the governor or any elected official, so taxpayers have absolutely no path to enforce accountability.


The quotation seems to belong to Meyer’s Coyote Blog. I would direct folks to the Reason Video on this issue.

However, maybe, there are just some words missing here, because the funding of state parks and global warming have some common policy issues.

Let me start with Global Warming. The case can be divided into two main areas. There is the science bit (the forecast warming and the catastrophic consequences) and the policy devised as a remedy (divided into the policy itself – the Legislation and actions – along with the expected / actual results). Or more simply Forecast, Consequences, Policy, and Outturn (FCPO).

In the UK, the Stern Review looked at this whole issue as a cost benefit analysis. By assuming fairly alarmist consequences (without the uncertainty) and assumes a relatively cheap (but highly effective) policy fix, gave benefits of the policy are 5 to 15 times the costs. It looks a clear-cut case for action, so anyone who denies this is either ignorant or has ulterior motives. But if you start assessing the uncertainty in the science, you will quickly find unverified hypotheses, implicit assumptions and measurement errors tending in the same direction. Furthermore the climate disruption consequential on this postulated warming is possibly more speculative still.

Even if you accept this worst case scenario with all the damaging consequences as the near certain, there is still the fact that the policies proposed (like Kyoto & Copenhagen) would only be cost-effective if each individual government implemented them like a business plan – maximising revenues and minimising costs. In Britain (with a legislated 80% CO2 reduction by 2050), the levels of costs are often many times the cost boundaries set by Stern, and there are many other costs being incurred that are at best side-shows (targets on recycling, banning incandescent light bulbs, alcohol in gasoline). Yet no Government will implement the policy with the necessary ruthlessness and doggedness required to get the positive results.

Like when Steve McIntyre looked into Mann’s hockey stick, what looks superficially to be robust falls apart when you start looking at it the totality. If absolute minimum for policy is to be an justifiable expectation of improving the likely future state as a result of taking action, then there should be some top-level independent auditing. As no independent review has taken place – like a bank reviewing a business plan to justify a loan – any major gaps or faults in any area potentially undermines the whole case for taking action. But when if the minimum requires accelerating warming, strong positive feedbacks; along with cheap and effective policies and zero issues with policy implementation or cost overruns; then there is a serious problem. So it is only by making a number of extreme and untenable assumptions that the consensus policy be supported. The overall solution is likely to be worse than the actual problem.

How does this relate to California’s state parks? Unlike for global warming, the case for action is clear. The parks need new funding for maintenance. The proposed policy would be ineffective in this, as it is not just funding levels at issue, as part of the cost problem is ineffective management. The solution of separating revenue from paying customers (or the electorate) will exacerbate the management issue. Furthermore, free access to all will increase visitor pressure, potentially hampering conservation efforts, whilst having an element of unfairness towards the inner-city poor. The overall solution is likely to be worse than the actual problem.