Previously, we had 29 excuses for “the pause” now we have 30.
When a paper is published by multiple authors, the universities of those authors often produce separate press releases to highlight the paper. Today, two separate press releases about the same paper showed up right next to each other in Eurekalert, as seen in the screen cap. Problem is though, one paper PR (from the University of New South Wales) places blame squarely on global warming, the other (from the University of Hawaii), only gives it a contributory mention. UNSW also expects a “sudden acceleration of global average surface temperatures”, but there’s no mention of that in the UH press release. Looking at the differences, it isn’t hard to spot the bias towards alarmism at UNSW.
Both press releases are presented in entirety below. Commentary follows.
From the University of New South Wales
Atlantic warming turbocharges Pacific trade winds
Record breaking trade winds may have led to hiatus in global surface average temperatures
New research has found rapid warming of the Atlantic Ocean, likely caused by global warming, has turbocharged Pacific Equatorial trade winds. Currently the winds are at a level never before seen on observed records, which extend back to the 1860s.
The increase in these winds has caused eastern tropical Pacific cooling, amplified the Californian drought, accelerated sea level rise three times faster than the global average in the Western Pacific and has slowed the rise of global average surface temperatures since 2001.
It may even be responsible for making El Nino events less common over the past decade due to its cooling impact on ocean surface temperatures in the eastern Pacific.
“We were surprised to find the main cause of the Pacific climate trends of the past 20 years had its origin in the Atlantic Ocean,” said co-lead author Dr Shayne McGregor from the ARC Centre of Excellence for Climate System Science (ARCCSS) at the University of New South Wales.
“It highlights how changes in the climate in one part of the world can have extensive impacts around the globe.”
The record-breaking increase in Pacific Equatorial trade winds over the past 20 years had, until now, baffled researchers.
Originally, this trade wind intensification was considered to be a response to Pacific decadal variability. However, the strength of the winds was much more powerful than expected due to the changes in Pacific sea surface temperature.
Another riddle was that previous research indicated that under global warming scenarios Pacific Equatorial Trade winds would slow down over the coming century.
The solution was found in the rapid warming of the Atlantic Ocean basin, which has created unexpected pressure differences between the Atlantic and Pacific. This has produced wind anomalies that have given Pacific Equatorial trade winds an additional big push.
“The rapid warming of the Atlantic Ocean created high pressure zones in the upper atmosphere over that basin and low pressure zones close to the surface of the ocean,” said Prof Axel Timmermann co-lead and corresponding author from the University of Hawaii.
“The rising air parcels, over the Atlantic eventually sink over the eastern tropical Pacific, thus creating higher surface pressure there. The enormous pressure see-saw with high pressure in the Pacific and low pressure in the Atlantic gave the Pacific trade winds an extra kick, amplifying their strength. It’s like giving a playground roundabout an extra push as it spins past.”
Many climate models appear to have underestimated the magnitude of the coupling between the two ocean basins, which may explain why they struggled to produce the recent increase in Pacific Equatorial trade wind trends.
While active, the stronger Equatorial trade winds have caused far greater overturning of ocean water in the West Pacific, pushing more atmospheric heat into the ocean, as shown by co-author and ARCCSS Chief Investigator Prof Matthew England earlier this year. This increased overturning appears to explain much of the recent slowdown in the rise of global average surface temperatures.
Importantly, the researchers don’t expect the current pressure difference between the two ocean basins to last. When it does end, they expect to see some rapid changes, including a sudden acceleration of global average surface temperatures.
“It will be difficult to predict when the Pacific cooling trend and its contribution to the global hiatus in surface temperatures will come to an end,” Prof England said.
“However, a large El Niño event is one candidate that has the potential to drive the system back to a more synchronized Atlantic/Pacific warming situation.”
Now from the University of Hawaii. Who says the Atlantic warming is “induced partly by greenhouse gasses”.
From the University of Hawaii ‑ SOEST
Atlantic origin of recent Pacific trade wind, sea level and temperature trends
An Australian–US team of climate researchers has solved a puzzle that has challenged scientists for over a decade. Climate models predict that the equatorial Pacific trades should weaken with increasing greenhouse gases. Yet, since the early 1990s, satellites and climate stations reveal a rapid and unprecedented strengthening of the Pacific trade winds, accelerating sea level rise in the western Pacific and impacting both Pacific and global climate.
“The answer to the puzzle is that recent rapid Atlantic Ocean warming has affected climate in the Pacific,” say the scientists. Their findings from observations and modeling experiments are published in the August 3, 2014, online issue of Nature Climate Change.
“We were surprised to find that the main cause of the Pacific wind, temperature, and sea level trends over the past 20 years lies in the Atlantic Ocean,” says Shayne McGregor at the University of New South Wales and lead author of the study. “We saw that the rapid Atlantic surface warming observed since the early 1990s, induced partly by greenhouse gasses, has generated unusually low sea level pressure over the tropical Atlantic. This, in turn, produces an upward motion of the overlying air parcels. These parcels move westward aloft and then sink again in the eastern equatorial Pacific, where their sinking creates a high pressure system. The resulting Atlantic–Pacific pressure difference strengthens the Pacific trade winds.”
“Stronger trade winds in the equatorial Pacific also increase the upwelling of cold waters to the surface. The resulting near-surface cooling in the eastern Pacific amplifies the Atlantic–Pacific pressure seesaw, thus further intensifying the trade winds,” says Axel Timmermann, corresponding author of the study at the University of Hawaii International Pacific Research Center. He comments further, “It turns out that the current generation of climate models underestimates the extent of the Atlantic–Pacific coupling, which means that they cannot properly capture the observed eastern Pacific cooling, which has contributed significantly to the leveling off, or the hiatus, in global warming.”
In contrast to previous studies that explain the eastern Pacific cooling as resulting solely from natural climate variability, the international climate research team points to a climate feedback that has been overlooked, namely, that the recent Atlantic warming affects the atmospheric circulation over the Pacific, leading to an increased persistence of cold ocean conditions there.
“It will be difficult to predict when the Pacific cooling trend and its contribution to the global warming hiatus will come to an end. The natural variability of the Pacific, associated for instance with the El Niño-Southern Oscillation, is one candidate that could drive the system back to a more even Atlantic–Pacific warming situation,” says co-author Matthew England from the University of New South Wales.
“Our study documents that some of the largest tropical and subtropical climate trends of the past 20 years are all linked: Strengthening of the Pacific trade winds, acceleration of sea level rise in the western Pacific, eastern Pacific surface cooling, the global warming hiatus, and even the massive droughts in California,” explains co-author Malte Stuecker from the University of Hawaii Meteorology Department.
“We are just starting to grasp the scope of the impacts of this global atmospheric reorganization and of the out-of phase temperature trends in the Atlantic and Pacific regions,” adds Fei-Fei Jin, climate scientist also at the University of Hawaii Meteorology Department.
Shayne McGregor, Axel Timmermann, Malte F. Stuecker, Matthew H. England, Mark Merrifield, Fei-Fei Jin, and Yoshimitsu Chikamoto: Recent Walker Circulation strengthening and Pacific cooling amplified by Atlantic warming.Nature Climate Change http://dx.doi.org/10.1038/nclimate2330.
Australian Research Council (ARC), including the ARC Centre of Excellence in Climate System Science. A.T. was supported through NSF grant No. 1049219. M.F.S. and F-F.J. were supported by US NSF grant ATM1034798, US Department of Energy grant DESC005110 and US NOAA grant NA10OAR4310200.
The only problem is, how would they explain similar but larger peaks in Atlantic Sea Surface Temperature, that have occurred before being “induced partly by greenhouse gasses”?
The The Atlantic multidecadal oscillation (AMO) was identified by Schlesinger and Ramankutty in 1994 in “An oscillation in the global climate system of period 65-70 years“.
In that paper abstract, they claim the AMO has “obscured” the global warming signal:
In addition to the well-known warming of ~0.5 °C since the middle of the nineteenth century, global-mean surface temperature records1-4display substantial variability on timescales of a century or less. Accurate prediction of future temperature change requires an understanding of the causes of this variability; possibilities include external factors, such as increasing greenhouse-gas concentrations5-7 and anthropogenic sulphate aerosols8-10, and internal factors, both predictable (such as El Niño11) and unpredictable (noise12,13). Here we apply singular spectrum analysis14-20 to four global-mean temperature records1-4, and identify a temperature oscillation with a period of 65-70 years. Singular spectrum analysis of the surface temperature records for 11 geographical regions shows that the 65-70-year oscillation is the statistical result of 50-88-year oscillations for the North Atlantic Ocean and its bounding Northern Hemisphere continents. These oscillations have obscured the greenhouse warming signal in the North Atlantic and North America. Comparison with previous observations and model simulations suggests that the oscillation arises from predictable internal variability of the ocean-atmosphere system.
Personally, I don’t think any of these climate scientists have a clue as to what they are talking about, much less what drives the climate in cycles.