Paul

According to Roger Pielke Sr, the answer is YES. He concludes: Thus the value of global warming of the last 4 years fails to agree with the IPCC projections (the values are not even close!). The agrument that this is too short of a time is spurious unless the modellers can account for where else in their model results the missing Joules went.

Moreover, this is not too short of a time period to compare with the models. Heat, unlike temperature at a single level as used to construct a global average surface temperature trend, is a variable in physics that can be assessed at any time period (i.e. a snapshot) to diagnose the climate system heat content. Temperature not only has a time lag, but a single level represents an insignificant amount of mass within the climate system.

The answer to the question on this weblog “Can the IPCC model projections of global warming be evaluated from just several years of observed data” is YES. The conclusion for the past four years is that the model projections are not skillful on this time period.

Roger Pielke Sr’s Climate Science Weblog: Can The IPCC Model Projections Of Global Warming Be Evaluated From Just Several Years Of Data?

“POLITICIANS seem to think that the science is a done deal,” says Tim Palmer. “I don’t want to undermine the IPCC, but the forecasts, especially for regional climate change, are immensely uncertain.”

Palmer is a leading climate modeller at the European Centre for Medium-Range Weather Forecasts in Reading, UK, and he does not doubt that the Intergovernmental Panel on Climate Change (IPCC) has done a good job alerting the world to the problem of global climate change. But he and his fellow climate scientists are acutely aware that the IPCC’s predictions of how the global change will affect local climates are little more than guesswork. They fear that if the IPCC’s predictions turn out to be wrong, it will provoke a crisis in confidence that undermines the whole climate change debate.

On top of this, some climate scientists believe that even the IPCC’s global forecasts leave much to be desired. …

A subscription is required to read the full New Scientist article: Poor forecasting undermines climate debate

Jasper Kirkby of CERN has published a new paper examining the potential link between cosmic rays and climate.

The paper concludes:

Numerous palaeoclimatic observations, covering a wide range of time scales, suggest that galactic cosmic ray variability is associated with climate change. The quality and diversity of the observations make it difficult to dismiss them merely as chance associations. But is the GCR flux directly affecting the climate or merely acting as a proxy for variations of the solar irradiance or a spectral component such as UV? Here, there is some palaeoclimatic evidence for associations of the climate with geomagnetic and galactic modulations of the GCR flux, which, if confirmed, point to a direct GCR-climate forcing. Moreover, numerous studies have reported meteorological responses to short-term changes of cosmic rays or the global electrical current, which are unambiguously associated with ionising particle radiation.

Cosmic ray forcing of the climate could in principle operate on all time scales from days to hundreds of millions of years, reflecting the characteristic time scales for changes in the Sun’s magnetic activity, Earth’s magnetic field, and the galactic environment of the solar system. Moreover the climate forcing would act simultaneously, and with the same sign, across the globe. This would both allow a large climatic response from a relatively small forcing and also give rise to simultaneous regional climate responses without any clear teleconnection path. The most persuasive palaeoclimatic evidence for solar/GCR forcing involves sub-orbital (centennial and millennial) climate variability over the Holocene, for which there is no established forcing agent at present. Increased GCR flux appears to be associated with a cooler climate, a southerly shift of the ITCZ (Inter Tropical Convergence Zone) and a weakening of the monsoon; and decreased GCR flux is associated with a warmer climate, a northerly shift of the ITCZ and a strengthening of the monsoon (increased rainfall). The influence on the ITCZ may imply significant changes of upper tropospheric water vapour in the tropics and sub-tropics, potentially affecting both long-wave absorption and the availability of water vapour for cirrus clouds.

The most likely mechanism for a putative GCR-climate forcing is an influence of ionisation on clouds, as suggested by satellite observations and supported by theoretical and modelling studies. The satellite data suggest that decreased GCR flux is associated with decreased low altitude clouds, which are known to exert globally a net radiative cooling effect. Studies of Forbush decreases and solar proton events further suggest that decreased GCR flux may reduce high altitude (polar stratospheric) clouds in the Antarctic. Candidate microphysical processes include ion-induced nucleation of new aerosols from trace condensable vapours, and the formation of relatively highly charged aerosols and cloud droplets at cloud boundaries, which may enhance the formation of ice particles in clouds and affect the collision efficiencies of aerosols with cloud droplets. Although recent observations support the presence of ioninduced nucleation of new aerosols in the atmosphere, the possible contribution of such new particles to changes in the number of cloud condensation nuclei remains an open question. Furthermore, the parts of the globe and atmosphere that would be expected to be the most climatically sensitive to such processes are unknown, although they are likely to involve regions of low existing CCN concentrations.

Despite these uncertainties, the question of whether, and to what extent, the climate is influenced by solar and cosmic ray variability remains central to our understanding of the anthropogenic contribution to present climate change. Real progress on the cosmic ray-climate question will require a physical mechanism to be established, or else ruled out. With new experiments planned or underway, such as the CLOUD facility at CERN, there are good prospects that we will have some firm answers to this question within the next few years.

Kirkby, J. 2008. Cosmic rays and climate. Surveys in Geophysics 28: 333-375.