Doug Hoffman: Atlantic Currents Cause European Climate Change Date: 22/10/12 The Resilient Earth Climate change alarmists point to the past several decades of European weather to reinforce their claim that global warming has the continent in its grip. A new report shows that this recent warm spell is nothing abnormal or unprecedented—during the 1990s there was simply a return to conditions present during 1931-1960. The reason for the shift is warm ocean temperatures that are, in turn driven by variation in warm ocean currents from the tropics. The instrumental record shows that, relative to the average temperature of the rest of the world’s oceans, the temperature of the North Atlantic Ocean has fluctuated between anomalously warm and anomalously cool phases, each lasting several decades at a time. Palaeoclimate records suggest that similar variations extend much farther back in time. The observed pattern of multidecadal variation in North Atlantic sea surface temperatures (SSTs) has become known as the Atlantic Multidecadal Oscillation (AMO). Climate change happens in cycles both long and short. The most dramatic long cycle that humans have experienced is the alternating ice age phenomenon of glacial and interglacial periods. Over the past 800,000 years or so, the world freezes for 100,000 years and then suddenly thaws for 15-25,000 years. Among the best known short cycles are the alternating El Niño/La Niña conditions in the Pacific, which gets blamed for bad weather in North America and failed monsoons in Asia. There are, however, a number of intermediate cycles that function on scales of decades to hundreds of years. Such cycles are problematic for climate scientists—it is very difficult to tell the difference between a cyclic swing and a human influenced change. It is very easy to observe a rise in temperature that waxes and wanes over a period of half a century and mistake that for something caused by human activity. A new Nature report, “Atlantic Ocean influence on a shift in European climate in the 1990s,” by Rowan T. Sutton and Buwen Dong, takes a look at one such intermediate length cycle that has been confusing climate scientists in Europe for decades. Here is the abstract: European climate exhibits variability on a wide range of timescales. Understanding the nature and drivers of this variability is an essential step in developing robust climate predictions and risk assessments. The Atlantic Ocean has been suggested as an important driver of variability in European climate on decadal timescales, but the importance of this influence in recent decades has been unclear, partly because of difficulties in separating the influence of the Atlantic Ocean from other contributions, for example, from the tropical Pacific Ocean and the stratosphere. Here we analyse four data sets derived from observations to show that, during the 1990s, there was a substantial shift in European climate towards a pattern characterized by anomalously wet summers in northern Europe, and hot, dry, summers in southern Europe, with related shifts in spring and autumn. These changes in climate coincided with a substantial warming of the North Atlantic Ocean, towards a state last seen in the 1950s. The patterns of European climate change in the 1990s are consistent with earlier changes attributed to the influence of the North Atlantic Ocean and provide compelling evidence that the Atlantic Ocean was the key driver. Our results suggest that the recent pattern of anomalies in European climate will persist as long as the North Atlantic Ocean remains anomalously warm. The key phrase here is “last seen in the 1950s.” A careful review of historical data reveals that what has happened in Europe over the past couple of decades has happened before—more than half a century before. Noting that “anomaly” simply means variation from some chosen baseline, the patterns of surface air temperature (SAT) anomalies over Europe for the two warm periods are very similar, as shown in the figure below. Anomalies in SAT during the recent warm phases of the AMO, relative to the intervening cool phase. In all three seasons, warm anomalies are found, but there is seasonal variation. In spring, significant warm anomalies are limited to western Europe, with the largest anomalies (>0.8°C) over continental western Europe. In summer, warm anomalies extend much further east into central and eastern Europe and the largest anomalies (>1.0°C) are found in the southern regions bordering the Mediterranean Sea. In autumn, in contrast, warm anomalies are limited to northern Europe, and the largest anomalies (>1.0°C) are found over Scandinavia. The similarity between the two warm periods can also be seen in the seasonal evolution of Central England Temperature (CET). These results are consistent with the seasonal mean correlations between the AMO and CET reported by other studies and suggest that the warm state of the North Atlantic favors a mild spring (especially April), summer and autumn, in England and across Europe. There are also characteristic anomalies in precipitation that accompany this cyclic trend, see the paper for details. Bottom line, the Atlantic Ocean is driving climate in Europe. Our results enhance significantly the growing body of evidence that the Atlantic Ocean is a key driver of decadal variability in the climate of Europe and other regions. They also suggest that the recent pattern of wet summers in northern Europe and hot, dry summers in southern Europe (and the related patterns of warm, dry, springs in northwestern Europe, warm dry autumns in Scandinavia, and wet autumns in southeastern Europe) may be expected to continue as long as the present warm phase of the AMO persists. However, it is uncertain how long this will be. This uncertainty reflects gaps in the understanding of the factors that drive the AMO. Interestingly, this new study’s results are in good agreement with some recently discovered 80 year old photographs from Greenland. Those photos revealed that this is not the first time that there has been a period of glacial retreat in Greenland. Current glacial melting is counted as yet another sign of the climate apocalypse by global warming true believers. Unfortunately for them, the glaciers of Greenland were shrinking about as fast during the 1930s as today’s “unprecedented” rate. The AMO drives Europe’s climate on a multidecadal time scale. The point is, much of the rise in temperature since the 1970s can be attributed to the onset of the warm phase of this North Atlantic cycle. The proximate cause of the cycle is strengthening and weakening of the meridional overturning current (MOC), the much ballyhooed ocean conveyor belt. Scientists studying the MOC will tell you the strength of its flow has varied widely over time and there is no reason to expect it not to change in the future. So, if Europe has been in the warm phase of a decades long cyclic climate phenomenon, temperatures in Europe should have peaked in the late 1990s and stayed there, more or less. If, instead, the warming over the past several decades was due to that dread scourge, CO2, the temperature trend should have been ever increasing as greenhouse gas levels have risen. Aye, there’s the rub. You see, data quietly released by the UK Met Office show that, from the beginning of 1997 until August 2012, there was no discernible rise in aggregate global temperatures. In other words, the world stopped getting warmer almost 16 years ago. The trend is shown in the figure below. Graph showing 16 years of temperature variation. As reported by the UK’s Daily Mail, the new data, compiled from more than 3,000 measuring points on land and sea, was issued quietly on the internet, without any media fanfare. “This stands in sharp contrast to the release of the previous figures six months ago, which went only to the end of 2010 – a very warm year,” the online article states. “Ending the data then means it is possible to show a slight warming trend since 1997, but 2011 and the first eight months of 2012 were much cooler, and thus this trend is erased.” So much for scientific objectivity from the Met Office. The Daily Mail asked a few climate experts for their opinion: Some climate scientists, such as Professor Phil Jones, director of the Climatic Research Unit at the University of East Anglia, last week dismissed the significance of the plateau, saying that 15 or 16 years is too short a period from which to draw conclusions. Others disagreed. Professor Judith Curry, who is the head of the climate science department at America’s prestigious Georgia Tech university, told The Mail on Sunday that it was clear that the computer models used to predict future warming were ‘deeply flawed’. Even Prof Jones admitted that he and his colleagues did not understand the impact of ‘natural variability’ – factors such as long-term ocean temperature cycles and changes in the output of the sun. However, he said he was still convinced that the current decade would end up significantly warmer than the previous two. Funny, when we had a decade of warming temperatures, the trend was “obvious” and a sure sign of impending global meltdown. Now tell me that scientific shills for anthropogenic global warming, like the good Dr. Jones, are truthful in their evaluation of climate data. Dr. Curry gets it right—the computer models that all this IPCC global warming flap-doodle is built on are deeply flawed. As a computer scientist and modeler, I have been saying that for years. Perhaps the media will finally get their heads out of the sand and see the truth—global warming is a scam perpetrated by a number of poor scientists in order to boost their egos and ensure public research funding. Perhaps the IPCC will issue their next report and say “just kidding about that end of the world as we know it stuff.” Perhaps pigs will fly. The sad truth is that too many climate scientists have gone on record supporting anthropogenic global warming as a dire crisis. Too many reputations and careers are on the line for a retraction. The best thing for these misguided savants to do is stay silent and slide quietly into retirement, but alas, they will not. As Max Plank said: “Truth never triumphs — its opponents just die out. Science advances one funeral at a time.” Be safe, enjoy the interglacial and stay skeptical.
Posted on: Thu, 06 Jun 2013 05:12:40 +0000
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