Friday, February 26, 2010

Sea level paper withdrawn on account of miscalculation

 Nature.com- February 24, 2010

Scientists have last week retracted a study which, based on simulations of the past 22,000 years, had projected a 21st century global sea level rise between 7 and 82 centimetres. The authors say they no longer have confidence in the projections owing to serious mistakes in their model approach.

The results, published last year in Nature Geoscience, had been roughly consistent with projections by the International Panel on Climate Change (IPCC) which in its 2007 report gave a range of 18-59 centimetres sea level rise by 2100. However, some scientists caution that the IPCC numbers, which exclude the effect of changing Greenland and Antarctic ice sheets, could prove too conservative.

Mark Siddall and his co-authors (including Thomas Stocker, co-chair of the IPCC’s working group on the physical basis of climate change) had used an empirical model linking sea-level rise to changes in global mean temperature. They had their model move forward in discreet 100-year time-steps which, although sufficient for simulating the past, they later found too coarse for reliably projecting future changes.

The study also failed to properly take into account uncertainties in temperature reconstructions of the last 2,000 years.

It is unclear if the resulting projections over- or underestimate future sea level rise, says Siddall.

The mistakes, he says, are too profound to be dealt with in a mere correction to the initial paper.

The retracted paper has been “totally independent” from studies reviewed by the IPCC for its last report, and will not affect future work by the IPCC, he says.

Tuesday, February 23, 2010

Grenada: Tackling Climate Change

Source: UN-DESA

Date: 23rd February 2010

Rising sea levels, intensified storms, eroding coastlines; these are all signs of global warming. Fluctuating temperatures and erratic weather patterns are now wrecking havoc in vulnerable Island nations.

The last time the small Caribbean island state of Grenada was hit by a hurricane was 55 years ago. Considering the time lapse, it is understandable that the more than 100’000 residents were very shocked with the five hour passage of hurricane Ivan in 2004. Grenada has been long thought to be too south of the hurricane belt to be impacted. This paradigm is shifting.

Visit the link http://bit.ly/aKJchj to view a short film on the way forward for Grenada, the impacts of climate change and the views of the nation in what needs to be done. This video is a product of the United Nations Department of Public Information in partnership with UN-DESA.



Sunderbans will drown in 60 yrs: WWF

From: Times India

KOLKATA: The World Wildlife Fund has warned that days are numbered for much of the sensitive Sunderbans eco-system and in 60 years vast tracts of the rare mangrove forests, home to the Bengal tiger, will be inundated by the rising sea.
The study, focussed on Sunderbans in Bangladesh, says the sea was rising more swiftly than anticipated by Intergovernmental Panel on Climate Change (IPCC) in 2007 and would rise 11.2 inches (above 2000 levels) by 2070. This would result in shrinkage of the Bangladesh Sunderbans by 96% within half a century, reducing the tiger population there to less than 20, said the study.
Unlike previous efforts, WWF's deputy director of conservation science Colby Loucks and his colleagues used a high-resolution digital elevation model with eight estimates of sea level rise to predict the impact on tiger habitat and population size. The team was able to come up with the most accurate predictions till date by importing over 80,000 Global Positioning System (GPS) elevation points.
The study, Sea Level Rise and Tigers: Predicted Impacts to Bangladesh's Sunderbans Mangroves, has been published in the journal, Climatic Change. Though the Indian part of the Sunderbans will not be so badly affected, conservationists wonder how many tigers would be able to survive here with nearly 60% of the habitat gone. Of the total Sunderbans, nearly 60% is in Bangladesh. Tigers do not recognize international borders though and cross over from one side to the other as and when they choose.
Experts say that every tiger requires a large territory of its own (known as range). An ever-spreading human habitat in the Indian part has already resulted in a drop in the big cats' territory, leading to frequent incidents of straying.
``Tigers have adapted to a life in the mangroves and crabs constitute an important part of their diet. Though tigers are a highly adaptable species, occupying territory from the snowy forests of Russia to the tropics of Indonesia, the projected sea level rise in the Sunderbans may outpace the animal's ability to adapt,'' a WWF source said. There are no accurate estimates, but conservationists estimate the mangroves could be home to upto 400 big cats.
The sea level rise will also have an impact on the lives of people who depend on the Sunderbans for their livelihood. The mangroves protect human habitation from cyclones and other natural disasters.
WWF has recommended that governments and natural resource managers take immediate steps to conserve and expand mangroves while preventing poaching and retaliatory killing of tigers. Neighbouring countries should increase sediment delivery and freshwater flows to the coastal region to support agriculture and replenishment of the land.