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Sun Not a Significant Driver of Climate Change
damn_registrars writes "Scientists from Edinburgh, Scotland have recently published a study based on 1,000 years of climate data. They have compared the effects of differing factors including volcanic activity, solar activity, and greenhouse gases to find which has the most profound effect on climate. They have concluded that the driving factor since 1900 has been greenhouse gases."
I see you did not actually look at the Nature paper they published. The title is: "Small influence of solar variability on climate over the past millennium". The key word is variability. As in variations in solar activity aren't a major driver in climate change, not the Sun itself.
In other words, you are the loon.
How did the world warm up and cool down before then? Perhaps that is relevant?
Over geologic times, lots of things have affected Earth's climate. On astronomical time scales the Sun has an impact: as it ages the Sun emits more radiation: it becomes warmer. But not on human timescales, or even moderate geological time scales. 600 million years ago the Sun was about 4% cooler. That means over the last 15 million years the Sun's radiation has probably increased by about 0.1%. Oceanic circulation has a major role: as continents move around they alter how the oceans transport and circulate heat. Volcanism also has a significant impact, but that impact is tricky to work out: increased CO2 adds to the greenhouse effect, but other volcanic emissions like dust and SO2 have a net cooling effect on the surface of the Earth. The Deccan traps, for example, is believed to have caused significant cooling during their formation.
Life, on long time scales, also causes an effect, Much of the petroleum the industrial revolution is burning and adding to current CO2 levels came primarily from the Carboniferous period. During that time Earth had a warm and humid climate promoting the development of huge rainforests worldwide. These plants photosynthesized so much carbon out of the atmosphere that CO2 levels dropped from something like 1400ppm to 400ppm. That caused the climate to cool significantly over a few hundred million years until it became colder and drier. The rainforests died off, and with the rainforests gone atmospheric CO2 began to rise again, increasing temperatures again.
Actually, over Earth's history the largest contributors to climate change have been atmospheric greenhouse gases, oceanic circulation currents, and the configuration of the continents. Two of the three are things human activity is demonstrated to be capable of altering on timescales many times faster than they have changed in Earth's history.
Look at it this way. The variance in solar radiation over a thousand year period is less than 0.01% of the variability seen in global temperature increase during the same period. In other words, the variability in solar radiative output (insolation) is far too small to explain the wide range of variance in global warming since the onset of the industrial revolution. In contrast, increase in carbon dioxide, as expected from the physics of its absorbtion spectrum explains cha.nge in temperature quite well (in fact it explains it rather well over the past 500 million years if isotope data is evalatuated).
It should be noted that there is no 18 years pause in global warming of sea temperature records. In fact, if one uses the arbitrary 18 year intervals to assess global atmospheric climate change, the record still shows global warming. Its just that within the last 18 years it has not been increasing as fast as the average over the last 100. Consequently, no one should be surprised that November 2013 proved to be the warmest November in recorded human history.
Or you could learn to read what they are actually saying, and stop listening to the made up crap you invent in your head.
Variations in solar output is not the key driver behind climate variation since 1900AD. That's it. Note the decided lack of dismissal of the sun as an energy source, or of the possibility that the sun could have been the primary driver of climate change. People suggested it, so they checked a millennium's worth of proxy data, and they showed a marked disconnect between the trends in solar and climate activity that appears in the last 100 years. This reconfirms similar studies over the last 20 years that have shown the same thing. Science.
"They aren't saying that the climate is not affected by changes in solar radiation."
That's what they're saying. But they're offering absolutely nothing new here. This is merely a review of others' past (perhaps too long past) work.
What they do say (section 6.4, "climate change", which is their conclusive paragraph) is:
"Extensive climate model studies have indicated that the models can only reproduce the late twentieth century warming when anthropogenic forcing is included, in addition to the solar and volcanic forcings [IPCC, 2007]. The change in solar radiative forcing since 1750 was estimated..."
Here is a plain English translation. (This bit is pretty important.)
"Climate model studies by other people can only reproduce the late twentieth century warming when anthropogenic radiative forcing is included."
This paper actually claims no new evidence that Anthropogenic Global Warming (CO2 AGW) is actually occurring. Their own statements (their own concluding paragraph above if you read the whole thing) says that they are relying on past studies to come to that conclusion. Other people concluded that. And they cite as a reference, an old IPCC report. The newer IPCC report is much toned down from the 2007 version they cite.
Not much to see here, and certainly nothing new, by their own admission. Move along now.
I should also point out that the entire concept of "radiative forcing" this is based on was refuted a few years ago, and so far that refutation has not been successfully challenged.
The UK getting record snowfall despite AGWers claiming the UK wouldn't see snow after 2008.
It goes back and forth. In 2000, they were saying that AGW would get rid of snow. In 2008, they were saying the snow was a result of AGW.
No doubt you will see a reversal again when there is no snow.
"First they came for the slanderers and i said nothing."
the now decade long pause in global warming.
Except that's not actually a thing. It's a deliberate misreading of data by people who are lying to you for political reasons. (Specifically, separating out selective readings (variations in surface temps) from broader data which shows a pretty constant heating effect, and falsely presenting the selective readings as "Global temperatures".)
Science is all about firing a drunk pig out of a cannon just to see what happens.
Grasping at straws indeed. This is the map for November, and you're telling me that the AGW folks are grasping at straws?
http://www.ncdc.noaa.gov/sotc/service/global/map-percentile-mntp/201311.gif
The pause in temperature rise has been written off as merely the effect of solar minimum.
The supposed "pause" is only surface temps, which is caused by the El Niño dominated cycle of the 1990s switching to a La Niña dominated cycle since 2000. This changed the warming pattern from surface dominated to deep ocean dominated (due to the shift in trade-winds exposing different layers of ocean.) This has been known for... well, I've known it for nearly a decade. (It's also known that this normally correlates with a marked cooling of global surface temps (such as in the 1940s), but this cycle is notable that there's still a (slower) rise in surface temps in spite of being a strong "cooling" cycle.)
What is new and interesting is the correlation between the decline in sunspot activity during the same decade as the La Niña dominance. So some researchers wonder if variations in solar activity are a factor in the decadal variation in the El Niño/La Niña cycle.
The is completely different from the research in TFA, which concerns the longer term climate trends, for which there is good correlation with solar output variations across the last 1000 years, except over the last century. The last hundred years are a new thing which needs a factor besides solar variation, the most parsimonious explanation is changes to levels of known greenhouse gases.
Now, it should tell you something about the progress of climate science that the researchers are drilling down and teasing out specific smaller parts of how the climate works in detail; while opponents of the existence of climate change are still stuck on the first page. But I suspect it doesn't.
Science is all about firing a drunk pig out of a cannon just to see what happens.
Agree that the Sun is the source of all the energy in the climate. The composition of the earth's Atmosphere, oceans and crust, have been likened to the "thermostat" in that they can absorb or reflect that energy to varying degrees.
CO2 has been a major factor in climate for a looooong time, at least as far back as the Cambrian explosion since CO2 is what melted "snowball" earth prior to the Cambrian explosion. CO2 can be both a "feedback" (melting permafrost) or a "forcing" (volcanos, human emissions). When acting as a feedback it always amplifies the direction of the change. We have known about CO2's major role since the 1950's when improved spectrometers finally pinned down it's role in the ice ages, ( Milankovich cycles alone cannot account for the magnitude of the changes observed in the ice ages).
Our best estimates of an important metric called "climate sensitivity" come from Fourier's formula and paleoclimatology (aka-geology). Fourier's formula alone gives ~1.5C rise for a doubling of CO2 but that assumes Earth is an ideal black body, which it is not. Adding geological evidence to estimate the feedback component brings it up to ~3.0C, the error bars are between 1.5c and 4.5C for a doubling of CO2, with the upper limit being far less certain then the lower. The uncertainty at the upper end is due to the lack of knowledge on things like frozen methane in deep ocean beds. The recent IPCC report downgraded the risk from sudden "tipping points" so the current high end estimate of climate sensitivity (whatever it is exactly) has a smidge more certainty than the previous report.
Disclaimer, IANACS, just a layman with a 30yr interest in the subject, don't rely on what my aging neurons tell you, WP is your friend for climate facts and trivia and I'm more than happy to be (politely) corrected.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.