No consensus on ice and global sea level projections based on Antarctic and Greenland data-Nature Geoscience paper. Current sea level rise 2mm/yr.

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7/14/13, "Limits in detecting acceleration of ice sheet mass loss due to climate variability," Nature Geoscience

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7/15/13, "'There is no scientific consensus' on sea-level rise, say scientists," UK Register, Lewis Page. "Just don't have enough data to say what'll happen."

"There isn't enough data to say with any certainty what will happen to sea levels around the world this century, and there is no "scientific consensus" to suggest that the rate of the seas' rise will accelerate dangerously.

That's according to a group of eminent specialists based in Germany, the Netherlands and the UK. Writing in hefty boffinry journal Nature Geoscience this week, the assembled experts have this to say:

The Greenland and Antarctic ice sheets have been reported to be losing mass at accelerating rates ... However, at present there is no scientific consensus on whether these reported accelerations result from variability inherent to the ice-sheet–climate system, or reflect long-term changes ...

[Our emphasis.]

The Greenland and Antarctic ice sheets are very important factors in forecasting the rate at which the seas might rise in the coming century, which is perhaps the primary reason to be concerned about global warming and associated climate changes.

During the 20th century, sea levels as measured by tide gauges rose about 17cm, just short of 2mm a year. The most recent report of the Intergovernmental Panel on Climate Change said that "no long-term acceleration of sea level has been identified using 20th-century data alone", but the organisation nonetheless forecast rises in the 21st century of 26-59cm as many scientists think that the rate of rise will increase seriously due to global warming.

Many others boffins assess that the ice sheets are so massive that they will take centuries to respond to likely levels of warming. Recent first-of-its-kind analysis pulling together all the factors in play suggested that the worst possible case in 2100 would be 30cm with the likely result less - in other words, no major change from the 20th century situation. And that was before new studies came out reflecting the fact that global warming has been basically on hold for the last decade and more, meaning that warming forecasts should be revised downwards.

Be all that as it may, the next IPCC report is now being produced. It will attempt to reflect what the various committees and advisors believe to be the scientific consensus on various matters including sea levels. But it appears that there simply isn't any scientific consensus on the Antarctic and Greenland melt rates - and therefore there isn't one on sea levels either.

You wouldn't necessarily know this. Various organisations, for instance the Google-funded alarmist activism organisation Climate Central, say that there is a consensus and that it centres on a much higher figure - one or even two metres of rise by 2100. ("Scientists expect" this, we are told by the Google mouthpieces.)...

The scientists compiling the new assessment say that there simply isn't enough data yet (especially from the GRACE satellites which have lately produced such surprising results on glacier and ice sheet mass) to know what will happen. In the case of the Greenland ice sheet, at least another ten years of data will be required.

According to a Bristol uni statement released to highlight the research:

As a result, extrapolation of the current contribution to sea-level rise of the ice sheets to 2100 may be too high or low by as much as 35 cm. The study, therefore, urges caution in extrapolating current measurements to predict future sea-level rise.

IPCC drafters, take note." via Junk Science

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7/14/13, "Limits in detecting acceleration of ice sheet mass loss due to climate variability," Nature Geoscience

"The Greenland and Antarctic ice sheets have been reported to be losing mass at accelerating rates^{1, 2}. If sustained, this accelerating mass loss will result in a global mean sea-level rise by the year 2100 that is approximately 43 cm greater than if a linear trend is assumed². However, at present there is no scientific consensus on whether these reported accelerations result from variability inherent to the ice-sheet–climate system, or reflect long-term changes and thus permit extrapolation to the future³. Here we compare mass loss trends and accelerations in satellite data collected between January 2003 and September 2012 from the Gravity Recovery and Climate Experiment to long-term mass balance time series from a regional surface mass balance model forced by re-analysis data. We find that the record length of spaceborne gravity observations is too short at present to meaningfully separate long-term accelerations from short-term ice sheet variability. We also find that the detection threshold of mass loss acceleration depends on record length: to detect an acceleration at an accuracy within ±10 Gt yr⁻², a period of 10 years or more of observations is required for Antarctica and about 20 years for Greenland. Therefore, climate variability adds uncertainty to extrapolations of future mass loss and sea-level rise, underscoring the need for continuous long-term satellite monitoring."

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7/15/13, "Polar ice loss cause still unclear,"
UK Guardian, Tim Radford

"New research shows that glaciologists still cannot say for certain whether the Earth's north and south polar ice is melting faster."

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