Archives for April 2008

I am reminded of a February 2007 post over at Climate Audit on a Simon Holgate sea level changes paper published in GRL, and a related poster presentation. Holgate claimed that sea levels rose more in the first half of the 20th century, than in the second half. The same could be said for solar activity.

Plotting the sun spot data on to Holgate’s graph of sea level changes produces an interesting result:

Holgate 2007 Figure 2. Comparison of the global mean decadal rates of sea level change based on the nine records with the rates from the 177 stations used in HW04. All rates are corrected for glacial isostatic adjustment and inverse barometer effects. The shaded region indicates standard error. The sun spot numbers are from here.

The coincidence is good except for the last sunspot cycle. Note also that the sea level series are decade mid-point, so the sunspot series should be read as displaced 5 years to the left. Does this mean that the correlation is real, but the effect of CO2 or something else has become apparent during the last solar cycle? Who knows!?

Whilst on the subject of sea level rise, there is this graph below from NASA-GISS: Sea Level Rise, After the Ice Melted and Today

MWP = meltwater pulse. MWP-1A0, c. 19,000 years ago, MWP-1A, 14,600 to 13,500 years ago, MWP-1B, 11,500-11,000 years ago, MWP-1C, ~8,200-7,600 years ago.

I think the above graph puts modern sea level rise into perspective.

References:

Woodworth, P.L. A world-wide search for the 11-year solar cycle in mean sea-level records. Geophysical Journal of the Royal Astronomical Society. 80(3) pp743-755, 1985.

S. J. Holgate, On the decadal rates of sea level change during the twentieth century. GRL, 2007.

Rumours of the demise of Scottish skiing are beginning to look greatly exaggerated.

While many Alpine resorts have closed for the season, thousands of skiers are still enjoying perfect conditions in the Highlands.

Scotland’s five resorts have struggled for more than 15 years with the effects of global warming, and several have diversified into summer tourism. The perfect snow cover at CairnGorm this weekend follows the worst season on record last year.

There is even talk of skiing on midsummer’s day, as visitors make the most of the best spring snow conditions anyone can remember.

The Daily Telegraph: ‘Late snow gives Scots resorts a ski lift ‘

In amongst an article that contains yet another straw-man attack on cosmic rays via the BBC, there is something more interesting reported from the European Geosciences Union (EGU) meeting.

In periods of relatively intense particle activity, some areas of the Earth’s surface in both the Arctic and Antarctic are warmer while others become colder, showing differences of up to 2C or 3C compared to the long-term averages.

In periods of unusually low particle activity, the patterns are reversed.

The mechanism appears to be redistributing heat across the polar regions; there is no evidence for any overall warming or cooling, Dr Seppala added, nor that the scale of the effect has changed over time.

“The results were amazing, and I think it’s something significant that we have to take into account,” commented Katje Matthes from the Free University of Berlin, who chaired the EGU session which saw the new data presented.

“I think it’s rather a local effect,” she added, “and I don’t think it has a big impact on global temperatures.”

Read more here:

http://news.bbc.co.uk/1/hi/sci/tech/7352667.stm

There are several interesting climate related studies in this week’s Science magazine.

Greenland Ice Slipping Away but Not All That Quickly

Almost 6 years ago, a paper in Science warned of an unheralded environmental peril. Melted snow and ice seemed to be reaching the base of the great Greenland ice sheet, lubricating it and accelerating the sheet’s slide toward oblivion in the sea, where it was raising sea level worldwide (12 July 2002, p. 218).

A new study has confirmed that meltwater reaches the ice sheet’s base and does indeed speed the ice’s seaward flow. The good news is that the process is more leisurely than many climate scientists had feared. Glaciologist Richard Alley of Pennsylvania State University in State College says, “It matters, but it’s not huge.” The finding should ease concerns that Greenland ice could raise sea level a disastrous meter or more by the end of the century.

Read more at PHYSORG.com: Lakes of meltwater can crack Greenland’s ice and contribute to faster ice sheet flow

Coral Adaptation in the Face of Climate Change

IN THEIR REVIEW, “CORAL REEFS UNDER RAPID CLIMATE CHANGE and ocean acidification” (14 December 2007, p. 1737), O. Hoegh- Guldberg et al. present future reef scenarios that range from coral-dominated communities to rapidly eroding rubble banks. Notably, none of their scenarios considers the capacity for corals to adapt. The authors dismiss adaptation because “[r]eef-building corals have relatively long generation times and low genetic diversity, making or slow rates of adaptation [relative to rates of change].” We think the possibility of adaptation deserves a second look.

In the absence of longterm demographic studies to detect temporal trends in life history traits, predicting rates of adaptation, and whether they will be exceeded by rates of environmental change, is pure speculation. Indeed, where such data are available for terrestrial organisms they demonstrate that contemporary evolution in response to climate change is possible (7).

There’s another coral story in The Herald Sun: Scientists find corals flourishing on Bikini Atoll

Phytoplankton Calcification in a High-CO2 World

Ocean acidification in response to rising atmospheric CO2 partial pressures is widely expected to reduce calcification by marine organisms. From the mid-Mesozoic, coccolithophores have been major calcium carbonate producers in the world’s oceans, today accounting for about a third of the total marine CaCO3 production. Here, we present laboratory evidence that calcification and net primary production in the coccolithophore species Emiliania huxleyi are significantly increased by high CO2 partial pressures. Field evidence from the deep ocean is consistent with these laboratory conclusions, indicating that over the past 220 years there has been a 40% increase in average coccolith mass. Our findings show that coccolithophores are already responding and will probably continue to respond to rising atmospheric CO2 partial pressures, which has important implications for biogeochemical modeling of future oceans and climate.

Read more at Dot Earth: Some Plankton Thrive With More CO2