Climate & Climate Change

Global warming will stop until at least 2015 because of natural variations in the climate, scientists have said. Researchers studying long-term changes in sea temperatures said they now expect a “lull” for up to a decade while natural variations in climate cancel out the increases caused by man-made greenhouse gas emissions. The average temperature of the sea around Europe and North America is expected to cool slightly over the decade while the tropical Pacific remains unchanged. This would mean that the 0.3°C global average temperature rise which has been predicted for the next decade by the UN’s Intergovernmental Panel on Climate Change may not happen, according to the paper published in the scientific journal Nature.

UK Telegraph: Global warming may ‘stop’, scientists predict

BBC News website: Next decade ‘may see no warming’

Nature: Climate change: Natural ups and downs

Editor’s Summary: Decadal climate prediction

Warming Antarctic waters begin to cool

Antarctica’s deep ocean waters are getting colder after years of warming, say researchers who have just returned from a Southern Ocean voyage aboard the German research vessel Polarstern.

PASADENA, Calif. – Boosted by the influence of a larger climate event in the Pacific, one of the strongest La Niñas in many years is slowly weakening but continues to blanket the Pacific Ocean near the equator, as shown by new sea-level height data collected by the U.S.-French Jason oceanographic satellite.

This La Niña, which has persisted for the past year, is indicated by the blue area in the center of the image along the equator. Blue indicates lower than normal sea level (cold water). The data were gathered in early April.

The image also shows that this La Niña is occurring within the context of a larger climate event, the early stages of a cool phase of the basin-wide Pacific Decadal Oscillation. The Pacific Decadal Oscillation is a long-term fluctuation of the Pacific Ocean that waxes and wanes between cool and warm phases approximately every five to 20 years. In the cool phase, higher than normal sea-surface heights caused by warm water form a horseshoe pattern that connects the north, west and southern Pacific, with cool water in the middle. During most of the 1980s and 1990s, the Pacific was locked in the oscillation’s warm phase, during which these warm and cool regions are reversed. For an explanation of the Pacific Decadal Oscillation and its present state, see: http://jisao.washington.edu/pdo/ and http://www.esr.org/pdo_index.html .

A La Niña is essentially the opposite of an El Niño. During El Niño, trade winds weaken and warm water occupies the entire tropical Pacific Ocean. Heavy rains tied to the warm water move into the central Pacific Ocean and cause drought in Indonesia and Australia while altering the path of the atmospheric jet stream over North and South America. During La Niña, trade winds are stronger than normal. Cold water that usually sits along the coast of South America is pushed to the middle of the equatorial Pacific. A La Niña changes global weather patterns and is associated with less moisture in the air, and less rain along the coasts of North and South America.

“This multi-year Pacific Decadal Oscillation ‘cool’ trend can intensify La Niña or diminish El Niño impacts around the Pacific basin,” said Bill Patzert, an oceanographer and climatologist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The persistence of this large-scale pattern tells us there is much more than an isolated La Niña occurring in the Pacific Ocean.”

Sea surface temperature satellite data from the National Oceanic and Atmospheric Administration also clearly show a cool Pacific Decadal Oscillation pattern, as seen at: http://www.cdc.noaa.gov/map/images/sst/sst.anom.gif . The shift in the Pacific Decadal Oscillation, with its widespread Pacific Ocean temperature changes, will have significant implications for global climate. It can affect Pacific and Atlantic hurricane activity, droughts and flooding around the Pacific basin, marine ecosystems and global land temperature patterns.

“The comings and goings of El Niño, La Niña and the Pacific Decadal Oscillation are part of a longer, ongoing change in global climate,” said Josh Willis, a JPL oceanographer and climate scientist. Sea level rise and global warming due to increases in greenhouse gases can be strongly affected by large natural climate phenomenon such as the Pacific Decadal Oscillation and the El Nino-Southern Oscillation. “In fact,” said Willis, “these natural climate phenomena can sometimes hide global warming caused by human activities. Or they can have the opposite effect of accentuating it.”

Jason’s follow-on mission, the Ocean Surface Topography Mission/Jason-2, is scheduled for launch this June and will extend to two decades the continuous data record of sea surface heights begun by Topex/Poseidon in 1992. JPL manages the U.S. portion of the Jason mission for NASA’s Science Mission Directorate, Washington, D.C.

For more information on NASA’s ocean surface topography missions, see: http://sealevel.jpl.nasa.gov/ ; or to view the latest Jason data, visit: http://sealevel.jpl.nasa.gov/science/jason1-quick-look/ .
JPL is managed for NASA by the California Institute of Technology in Pasadena.

News Releases: Larger Pacific Climate Event Helps Current La Nina Linger
April 21, 2008

”We compare new observationally-based data sets of Antarctic near-surface air temperature and snowfall accumulation with 20th century simulations from global climate models (GCMs) that support the Intergovernmental Panel on Climate Change Fourth Assessment Report. Annual Antarctic snowfall accumulation trends in the GCMs agree with observations during 1960–1999, and the sensitivity of snowfall accumulation to near-surface air temperature fluctuations is approximately the same as observed, about 5% K−1. Thus if Antarctic temperatures rise as projected, snowfall increases may partially offset ice sheet mass loss by mitigating an additional 1 mm y−1of global sea level rise by 2100. However, 20th century (1880–1999) annual Antarctic near-surface air temperature trends in the GCMs are about 2.5-to-5 times larger-than-observed, possibly due to the radiative impact of unrealistic increases in water vapor. Resolving the relative contributions of dynamic and radiative forcing on Antarctic temperature variability in GCMs will lead to more robust 21st century projections.”

The above is the abstract from:

Monaghan, A. J., D. H. Bromwich, and D. P. Schneider (2008), Twentieth century Antarctic air temperature and snowfall simulations by IPCC climate models, Geophys. Res. Lett., 35, L07502, doi:10.1029/2007GL032630.

Roger Pielke Sr comments:

“This paper provides further evidence that the multi-decadal global climate models are significantly overstating the water vapor input into the atmosphere, and thus are not providing quantitatively realistic estimates of how the climate system responds to the increase in atmospheric well mixed greenhouse gases in terms of the water vapor feedback. This water vapor feedback is required in order to achieve the amount of warming from radiative forcing projected in the 2007 IPCC report.”

Using evidence from an Antarctic ice core, Zebee and Caldiera calculated that over a period of 610,000 years the long-term change in atmospheric CO2 concentration was just 22 parts per million volume (ppmv), although there were larger fluctuations associated with the transitions between glacial and interglacial conditions.

By comparison, two centuries of human industry have raised levels by about 100 ppmv.

BBC News website: Nature’s carbon balance confirmed

Nature Geoscience: Close mass balance of long-term carbon fluxes from ice-core CO2 and ocean chemistry records

Richard E. Zeebe & Ken Caldeira

The latest research from scientists in Antarctica reveals the deep ocean around the frozen continent is becoming less salty and that this could play a major role in changing ocean currents and the climate. New details about changes to salinity are coming from deep beneath the sea ice, courtesy of satellite tagged seals. This unique tracking program involving Australian scientists is part of a major international research program shedding new light on how the world’s oceans are changing.

ABC 7.30 Report Transcript: Satellite tagged seals shed light on climate change

On-line video report also available.

ABOUT the beginning of 2007, maintaining a sceptical stance on human-induced global warming became a lonely, uphill battle in Australia.

The notion that the science was settled had gathered broad popular support and was making inroads in unexpected quarters. Industrialists and financiers with no science qualifications to speak of began to pose as prophets. Otherwise quite rational people decided there were so many true believers that somehow they must be right. Even Paddy McGuinness conceded, in a Quadrant editorial, that on balance the anthropogenic greenhouse gas hypothesis seemed likelier than not.

What a difference the intervening 15 months has made. In recent weeks, articles by NASA’s Roy Spencer and Bjorn Lomborg and an interview with the Institute of Public Affairs’ Jennifer Marohasy have undermined that confident Anglosphere consensus. On Amazon.com’s bestseller list this week, the three top books on climate are by sceptics: Spencer, Lomborg and Fred Singer.

Read more here: http://www.theaustralian.news.com.au/story/0,25197,23597729-7583,00.html

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from The Australian, by Christopher Pearson, ‘A Cool Idea to Warm To’, April 26, 2008.