Study suggests volcanic eruptions behind pause in climate change
Over the last few years, many possible explanations have been bandied about for the so-called pause in climate change, a plateau in global surface air temperatures that is out of step with rising greenhouse gas concentrations. But now an international research effort is laying responsibility at the feet of volcanic eruptions, whose particles it has found reflect twice as much solar radiation as previously believed, serving to temporarily cool the planet in the face of rising CO2 emissions.
It has long been known that volcanic eruptions impact the climate, spewing ash and sulfur-rich particles into the atmosphere and blocking out the warmth of the sun. These eruptions had been factored into climate modeling, though it is now the view of an international group of scientists that their influence has been majorly understated.
Scientists from Sweden's University of Lund led a team involving the NASA Langley Research Center, Germany's Karlsruhe Institute of Technology (KIT) and the Royal Netherlands Meterological Institute. Its work sought to explain the negligible rise in average surface temperatures over the northern mid-latitude continents in the first decade of the 21st century.
The scientists drew on data collected over this area in the tropopause region, the border in the Earth's atmosphere that separates the troposphere and stratosphere. They used a two-part strategy to carry out their new study.
One part involved calling on samples and measurements routinely carried out by the In-service Aircraft for a Global Observing System (IAGOS) project, a Europe-based research initiative that monitors the composition of our atmosphere. The project has been measuring trace gases and aerosol particles in the tropopause region since 1997 by flying modified Airbus A340-600s loaded with scientific instruments through the area. Samples are collected and analyzed on the ground using ion beam accelerators to measure quantities of sulfur particles.
The second part of the study enlisted the services of NASA's Cloud-Aerosol Lidar and Pathfinder Satellite Observation (CALIPSO), a mission that collects satellite data on aerosol and cloud layers in the atmosphere. Though the satellite has been in use for some time, it had only looked at data above an altitude of 15 km (9.3 mi) where volcanic aerosol were known to impact our climate. The new study took into account the aerosol particles present in the lower part of the stratosphere, so the impact of smaller volcanic eruptions could be considered as well.
Combining and analyzing data from the two sources led the scientists to conclude that, while the impact of volcanic eruptions was small between 1999 and 2002, between 2005 and 2012 they had a big influence. They point to three eruptions in particular: Kasatochi, USA in August of 2008, Sarychev, Russia in June of 2009 and Nabro, Eritrea in June of 2011. They say that each belched out more than one megaton of sulfur dioxide into the atmosphere, where it converts into sulfur particles.
"The cooling effect of volcanic eruptions was underestimated in the past, because the lowest part of the stratosphere was mostly not considered.," says Dr Sandra M. Andersson from the University of Lund, one of the study's lead authors.
The scientists describe a range of factors determining whether or not volcanic eruptions go onto to shape the climate globally, including the amount of sulfur dioxide that is emitted. They found that the latitude of the eruption also plays a part, because air in the stratosphere in the Northern Hemisphere flows independently of that in the Southern Hemisphere. Therefore only volcanic eruptions that occur close to the equator can disseminate particles over both hemispheres. The research also uncovered evidence that the time of year is also a factor, with eruptions taking place in the summer, where solar radiation is stronger, found to have a bigger impact.
The reaearch was published in the journal Nature Communications.
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The global warming was stopped exactly in 1999.
After the very hot 1998, there was a 0,5 Celsius drop of global average temperature in 1999.
And since then, there is no global warming.
You can see it here:
So, recent vucanic activities can explain nothing.
Try an other explanatation :-)
However, it would be much simpler to admit, that we have no clue of the reasons of climate change.
Or are we in this settled scientific environment clutching at straws, retrospectively reconstructing data which wasn't collected at the time.
Given that the pause/hiatus/plateau is now well into its 19th year - actually, depending on which database you use, no statistically significant warming for between 18 and 26 years, it is unclear how the utter failure of over 100 climate models can be ascribed to an eruption that took place in 2009.
As to "a plateau in global surface air temperatures that is out of step with rising greenhouse gas concentrations", ice core analyses indicate that temperature change leads increased global temperature, it does not drive it.
I believe it is incontrovertible that the whole AGW debate revolves around the increase in temperature caused by a doubling in the concentration of atmospheric carbon dioxide - commonly referred to as climate sensitivity, and that over the past three decades many billions of dollars have been expended researching this extremely important value. A low value indicates that we have little or nothing to fear from a doubling of atmospheric carbon dioxide, a high value indicates that we may have a serious problem.
I doubt anyone on either side of the debate can disagree that this is a very important issue.
So let us see how much progress has been made over the last couple of decades pinning down this extremely important number.
The IPCC is commonly regarded as the most reputable authority on such matters, so let us see how estimates of the climate sensitivity have changed over the five IPCC Assessment Reports from 1990 to the present day, a period of some two and a half decades.
Here are the ranges of value given by the five IPCC Assessment Reports that have been published to date.
IPCC First assessment report 1.9°C to 5.2°C, but states “…hence the models results do not justify altering the previously accepted range of 1.5°C to 4.5°C**
IPCC Second Assessment Report 2°C to 4.5 C"
IPCC Third Assessment Report 1.5°C to 4.5 °C
IPCC Fourth Assessment Report 2°C to 4.5 °C
IPCC Fifth Assessment Report 1.5°C to 4.5°C
So, despite the expenditure of many, many billions of dollars on research, according to the IPCC estimates of the low and high limits of this essential parameter effectively have not changed in 25 years.
** The original 1.5 - 4.5°C estimate came from the Charney report of 1979.
It is all quite interesting.
This is a new dark ages. At least this article states there has been a pause since the IPCC data was compiled and showed no AGW. But why does it bother no one that no matter what we experience - the AGW people claim its all part of AGW. Cooling, warking, pausing, stopping, etc - they have made themselves never wrong... and people are dumb enough to buy into it.
So when do we get back all the millions we paid for emissions checking for that "helped" a non-existant rise in temps?
And... umm... volcanos were always cited as a huge cause of greenhouse gases. So AGAIN - no matter what happens, the AGW people claim it explains away a problem they are having with their fantasy.
It was OVER at Climate Gate 1. Was even more dead at Climate Gate 2. And when the IPCC data was compiled it was DEAD again. We all need to quit resurrecting this non-scientific propaganda.