Archives for October 12, 2007

A new paper predictably makes a big splash in this week’s Nature magazine:

Attribution of observed surface humidity changes to human influence

Katharine M. Willett1,2, Nathan P. Gillett1, Philip D. Jones1 & Peter W. Thorne2

Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
Met Office Hadley Centre, FitzRoy Road, Exeter EX1 3PB, UK

Water vapour is the most important contributor to the natural greenhouse effect, and the amount of water vapour in the atmosphere is expected to increase under conditions of greenhouse-gas-induced warming, leading to a significant feedback on anthropogenic climate change. Theoretical and modelling studies predict that relative humidity will remain approximately constant at the global scale as the climate warms, leading to an increase in specific humidity. Although significant increases in surface specific humidity have been identified in several regions and on the global scale in non-homogenized data, it has not been shown whether these changes are due to natural or human influences on climate. Here we use a new quality-controlled and homogenized gridded observational data set of surface humidity, with output from a coupled climate model, to identify and explore the causes of changes in surface specific humidity over the late twentieth century. We identify a significant global-scale increase in surface specific humidity that is attributable mainly to human influence. Specific humidity is found to have increased in response to rising temperatures, with relative humidity remaining approximately constant. These changes may have important implications, because atmospheric humidity is a key variable in determining the geographical distribution and maximum intensity of precipitation, the potential maximum intensity of tropical cyclones, and human heat stress16, and has important effects on the biosphere and surface hydrology.

Also in Nature News:

Humans have made the skies more moist

Study models rises in atmospheric water vapour.

Human activity is behind the rising levels of water vapour in the lower atmosphere over the past few decades, climatologists have concluded. The rises in humidity could affect patterns of extreme storms, they warn.

Nature’s editor likes it too:

Getting steamed up

………using a new data set of surface specific humidity observations, along with output from a coupled climate model, Willett et al. identify a significant increase in global mean surface specific humidity during the late twentieth century that is mainly attributable to human influence.

Luke Walker thinks the paper is significant and sent a link to ABC’s predictable take:

Rising humidity fuels greenhouse effect

We also had this report from the BBC in November 2005:

Water builds the heat in Europe

“Water vapour rather than carbon dioxide in the atmosphere is the main reason why Europe’s climate is warming, according to a new study.”

The BBC are up to speed with the new Nature paper:

Warmth makes the world more humid

I wonder how evaporation equalling precipitation globally over the past 20 years fits into this?

The paper also tries to make a link with increased tropical cyclones, but the case for a link is weak.

Scant publicity by comaprison for the recent Spencer et al paper ‘Cloud and radiation budget changes associated with tropical intraseasonal oscillations’. Geophys. Res. Lett., Vol. 34, No. 15, 9 August 2007.

Read the article ‘Global Warming and Nature’s Thermostat’ by Roy W. Spencer:

August 9, 2007 RESEARCH UPDATE!: Our peer-reviewed paper showing the natural cooling behavior of tropical cirrus clouds in response to warming has been published today in Geophysical Research Letters. (The UAH news release is here.) This natural cooling mechanism constitiutes a strong “negative feedback” (reducing warming tendencies), while all leading climate models have cirrus clouds behaving in a positive feedback manner (amplifying warming tendencies). As is usually the case in this business, however, there is no way to know with any level of confidence whether this mechanism is operating in the context of manmade global warming………

Study finds global warming affecting bird migration

Climate change may not be noticeable to all humans yet, but the behaviour of birds suggests the seasons have already changed.

A researcher at the weather bureau has found that some spring migrating birds are arriving many days earlier than they used to.

Short-term targets key to tackling climate change: report

A new report says a 30 per cent reduction in greenhouse emissions by 2020 is an achievable target for Australia.

Turnbull hints at ratifying new climate change agreement

Federal Environment Minister Malcolm Turnbull has signalled Australia may ratify the next international climate change deal that comes into effect when the Kyoto Protocol expires.

World energy revolution needed for climate: U.S.

UNITED NATIONS (Reuters) – U.S. Secretary of State Condoleezza Rice said on Monday the world needs a revolution on energy that transcends oil, gas and coal to prevent problems from climate change.

“Ultimately, we must develop and bring to market new energy technologies that transcend the current system of fossil fuels, carbon emissions and economic activity. Put simply, the world needs a technological revolution,” Rice told delegates at a special U.N. conference on climate change.

Thanks to Luke Walker for links to the following articles:

Government to ban plasma TVs?

Your new TV may soon be a consumer relic

Plans to ban plasma TV’s

The CSIRO 2007 Climate Report: an assertion-laden sales brochure by John McLean, October 2007

The report, “Climate change in Australia”, by the CSIRO and Bureau of Meteorology was released on 2
October 2007 and predicted a dire climatic future. The contents of the report have been widely accepted by politicians, the media and the public with hardly a murmur.

That’s a rather disturbing acceptance of a document that is loaded with vested interests, ignores various
temperature factors, unjustifiably minimises influence of a major climate force and lacks substantiation for
its most important claims.

In short it is little more than a sales brochure for the unproven claim that man-made emissions of carbon
dioxide are the cause of climate changes.

1. It contains a prior assumption that carbon dioxide has caused warming

From the very start of chapter one the report makes it clear that greenhouse gases will be the key focus, and
of course prime suspect, if such can be said of kangaroo courts.

In that chapter we are being softened up for a barrage of assertions and sure enough chapter 3 presents those
assertions by claiming that almost every climate variation in Australia over the last 50 years was caused by
anthropogenic emissions of carbon dioxide.

The CSIRO presents no evidence for this claim and the weight of its argument is based only on the repetition
of words. Readers are clearly expected to accept this at face value but a wide reading of relevant literature
shows plenty of reason to question it.

Delve a little deeper and the CSIRO report is largely based on the report of the Intergovernmental Panel on
Climate Change (IPCC). Explore the IPCC’s claims and the evidence there is also remarkably weak. First
we have an assumption that temperature data is accurate and that a loose but delayed correlation between the
increases in temperature and carbon dioxide is somehow evidence that carbon dioxide drives temperature.
Second is the assumption that climate models are accurate, which is difficult to believe when even the IPCC
admits that many climate factors are poorly understood.

In other words this CSIRO climate report is focused exclusively on an already-questionable premise and
provides no justification for doing so or evidence to support the premise.

Conclusion

If the 2007 CSIRO climate report makes any claims to be an impartial, thorough and accurate assessment of
the recent and future Australian climate then it does so under false pretences.

It is overwhelmingly biased towards greenhouse gases being the major cause of climate change since 1950
and yet produces absolutely no evidence for this assertion. Some natural forces are ignored and another that
is first highlighted as being linked to historical climate variations is subsequently dismissed as being minor
or irrelevant.

There is only one notion that matters to this report – that man-made emissions of carbon dioxide have a
major impact on climate. Come hell or high water, this report tries to ram that unproven notion into its
readers at every turn. Create climate models based on that assumption, never verify their accuracy and then
wave a consensus of results as if it was proof, that’s the process behind this report.

The report is, by and large, nothing more than a marketing document, one written by people with vested
interests, never subjected to any independent review and gravely biased towards a particular claim.

We would never accept without independent and impartial review an evaluation of a drug written by it’s own
researchers or an invitation to invest in shares that was written only by a company’s sales department so why
should we accept this CSIRO report without similar review?

It is an exceptionally sad reflection on Australian politicians, news media and the public that the report has
been so readily accepted as credible and the predictions treated as near-certainties

Read the full critique here.

The CSIRO report can be downloaded from here.