Archives for May 2008

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.

Blog readers may remember Prince Charles’ previous climate rantings during his ‘eco-friendly’ trip to the West Indies involving a £280,000 per week Yacht, when he spoke about the “sheer madness” of climate scepticism.

Now Climate Charlie is back with a new pronouncement:

The Prince of Wales has warned that the world faces a series of natural disasters within 18 months unless urgent action is taken to save the rainforests.

In one of his most out-spoken interventions in the climate change debate, he said a £15 billion annual programme was required to halt deforestation or the world would have to live with the dire consequences.

“We will end up seeing more drought and starvation on a grand scale. Weather patterns will become even more terrifying and there will be less and less rainfall,” he said.

“We are asking for something pretty dreadful unless we really understand the issues now and [the] urgency of them.” The Prince said the rainforests, which provide the “air conditioning system for the entire planet”, releasing water vapour and absorbing carbon, were being lost to poor farmers desperate to make a living.

Nothing much to do? Then read the rest of the recent Telegraph article: Prince Charles: Eighteen months to stop climate change disaster

Despite recent and continuing non-warming, it appears that the climate change disaster is moving ever closer. Blair gave us the need for a climate deal in 2 years or adaptation only by 2020, Gore 5 years to an ice-free Arctic, and now we have just 18 months. Rest assured, I will be verifying these predictions on their due dates.

Scientist Tim Flannery has proposed a radical solution to climate change which may change the colour of the sky.

But he says it may be necessary, as the “last barrier to climate collapse.”

Professor Flannery says climate change is happening so quickly that mankind may need to pump sulphur into the atmosphere to survive.

National Nine News: Change sky’s colour, proposes Flannery

Hurricanes and tropical storms will become less frequent by the end of the century as a result of climate change, US researchers have suggested.

But the scientists added their data also showed that there would be a “modest increase” in the intensity of these extreme weather events.

The findings are at odds with some other studies, which forecast a greater number of hurricanes in a warmer world.

The researchers’ results appear in the journal Nature Geoscience.

BBC News website: ‘Fewer hurricanes’ as world warms

Nature Geoscience: Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions

Abstract:

Increasing sea surface temperatures in the tropical Atlantic Ocean and measures of Atlantic hurricane activity have been reported to be strongly correlated since at least 1950 raising concerns that future greenhouse-gas-induced warming could lead to pronounced increases in hurricane activity. Models that explicitly simulate hurricanes are needed to study the influence of warming ocean temperatures on Atlantic hurricane activity, complementing empirical approaches. Our regional climate model of the Atlantic basin reproduces the observed rise in hurricane counts between 1980 and 2006, along with much of the interannual variability, when forced with observed sea surface temperatures and atmospheric conditions. Here we assess, in our model system, the changes in large-scale climate that are projected to occur by the end of the twenty-first century by an ensemble of global climate models, and find that Atlantic hurricane and tropical storm frequencies are reduced. At the same time, near-storm rainfall rates increase substantially. Our results do not support the notion of large increasing trends in either tropical storm or hurricane frequency driven by increases in atmospheric greenhouse-gas concentrations.