Arguments
Sun & climate: moving in opposite directions
What the science says...
| Select a level... |
Basic
|
Intermediate
|
Advanced
| ||||
|
The sun's energy has decreased since the 1980s but the Earth keeps warming faster than before. |
|||||||
Climate Myth...
It's the sun
"Over the past few hundred years, there has been a steady increase in the numbers of sunspots, at the time when the Earth has been getting warmer. The data suggests solar activity is influencing the global climate causing the world to get warmer." (BBC)
Over the last 35 years the sun has shown a cooling trend. However global temperatures continue to increase. If the sun's energy is decreasing while the Earth is warming, then the sun can't be the main control of the temperature.
Figure 1 shows the trend in global temperature compared to changes in the amount of solar energy that hits the Earth. The sun's energy fluctuates on a cycle that's about 11 years long. The energy changes by about 0.1% on each cycle. If the Earth's temperature was controlled mainly by the sun, then it should have cooled between 2000 and 2008.
Figure 1: Annual global temperature change (thin light red) with 11 year moving average of temperature (thick dark red). Temperature from NASA GISS. Annual Total Solar Irradiance (thin light blue) with 11 year moving average of TSI (thick dark blue). TSI from 1880 to 1978 from Krivova et al 2007. TSI from 1979 to 2015 from the World Radiation Center (see their PMOD index page for data updates). Plots of the most recent solar irradiance can be found at the Laboratory for Atmospheric and Space Physics LISIRD site.
The solar fluctuations since 1870 have contributed a maximum of 0.1 °C to temperature changes. In recent times the biggest solar fluctuation happened around 1960. But the fastest global warming started in 1980.
Figure 2 shows how much different factors have contributed recent warming. It compares the contributions from the sun, volcanoes, El Niño and greenhouse gases. The sun adds 0.02 to 0.1 °C. Volcanoes cool the Earth by 0.1-0.2 °C. Natural variability (like El Niño) heats or cools by about 0.1-0.2 °C. Greenhouse gases have heated the climate by over 0.8 °C.
Figure 2 Global surface temperature anomalies from 1870 to 2010, and the natural (solar, volcanic, and internal) and anthropogenic factors that influence them. (a) Global surface temperature record (1870–2010) relative to the average global surface temperature for 1961–1990 (black line). A model of global surface temperature change (a: red line) produced using the sum of the impacts on temperature of natural (b, c, d) and anthropogenic factors (e). (b) Estimated temperature response to solar forcing. (c) Estimated temperature response to volcanic eruptions. (d) Estimated temperature variability due to internal variability, here related to the El Niño-Southern Oscillation. (e) Estimated temperature response to anthropogenic forcing, consisting of a warming component from greenhouse gases, and a cooling component from most aerosols. (IPCC AR5, Chap 5)
Some people try to blame the sun for the current rise in temperatures by cherry picking the data. They only show data from periods when sun and climate data track together. They draw a false conclusion by ignoring the last few decades when the data shows the opposite result.
Basic rebuttal written by Larry M, updated by Sarah
Update July 2015:
Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial
This rebuttal was updated by Kyle Pressler in 2021 to replace broken links. The updates are a result of our call for help published in May 2021.
Last updated on 2 April 2017 by Sarah. View Archives
That chart shows temperatures continuously and sharpely increasing since 1980, that is pure nonsense. The most accurate measurements, satellite measurements, the ones the Clinate Scientists seem to choose to ignore shows flat temperatures from 1980 to 2000, with a few spikes. Then the reletively volcano free 2000 through today shows an increase of 0.2 degrees. As recent as 2008 we were at or below the level of 1980. If the best the (-snip-)highlighted by the original article starting this thread. http://www.drroyspencer.com/latest-global-temperatures/
"The most accurate measurements, satellite measurements, the ones the Clinate Scientists seem to choose to ignore shows flat temperatures from 1980 to 2000, with a few spikes"
Nonsense. UAH, a satellite measurement from climate "skeptics" Roy Spencer and John Christy, shows about .22*C of warming from 1980 to 2000. From 1980 to the present it shows about .42*C. You are completely wrong.
"As recent as 2008 we were at or below the level of 1980."
Nonsense again. 2008 was no where near as cool as 1980.
" If the best the (-snip-) can do is rely on highly innacurate ground measurements they don't have much of a case."
The ground measurements agree very well with the satellite data, which you are obviously are unfamiliar with. Nothing you said above is true. Talk about a . (-snip-)
Robert Wagner @ 1042, those same satellite measurements you claim to be accurate show a TOA energy imbalance: more energy entering the Earth system than leaving it. What do you think is happening to all that extra energy Earth is absorbing, if it is not warming the biosphere?
Robert Wagner @1041, below are 11 year running averages of Gistemp (as used in figure 1 above) post 1950, along with 11 year running averages of RSS and UAH data, all offset to have a common baseline of 1981-2010. As can clearly be seen, the trends of the three are virtualy indistinguishable. Your primary claim is, therefore, patently false.
I will also note that your supposition that the satellite records, by virtue of being satelite records, are more accurate records is unfounded. It is well known that the surface temperature record needs adjustment for the Urban Heat Island (UHI) effect, Time of Observation (TOBS), along with changes of instruments over time. The satellite record, however, invovles adjustments for changes of instruments (as one Satellite is replaced by another), for the fact that the raw data includes a large measure of the cooling stratosphere in its observations, for the fact that the time of observation at any location changes as the satellite orbits , for bias arising from the properties of different surfaces, and their altitudes; and so on. Far more, and far more mathematically challenging mathematical adjustments are required to take raw satellite records and turn them into a temperature record than are required for the surface record.
Below are a list of the main corrections of the main, known errors in the UAH record that have been needed over time (and acknowledged by Roy Spenser). There has been a scientific paper published pointing out yet another apparently needed correction that Dr Spencer does not yet agree with. Only time will tell if he has finally got it about right, or whether yet more corrections will be needed before UAH can finally be considered as accurate as the surface record:
Why are people even debating this The empirical evidence in favor of the solar explanation is overwhelming.
Dozens of peer-reviewed studies have found a very high degree of correlation (.5 to .8) between solar-magnetic activity and global temperature going back many thousands of years (Bond 2001, Neff 2001, Shaviv 2003, Usoskin 2005, and many others listed below). In other words, solar activity “explains,” in the statistical sense, 50 to 80% of past temperature change.
Such a high degree of correlation over such long time periods implies causality, which can only go one way. Global temperature cannot be driving solar activity, so there must be some mechanism by which solar activity is driving or modulating global temperature change. The high degree of correlation also suggests that solar activity is the primary driver of global temperature on every time scale studied (which is pretty much every time scale but the Milankovitch cycle).
In contrast, records of CO2 and temperature reveal no discernable warming effect of CO2. There is a correlation between atmospheric CO2 and temperature, but with CO2 changes following temperature changes by an average of about 800 years (Caillon 2003), indicating that it is temperature change that is driving atmospheric CO2 change (as it should, since warming oceans are able to hold less CO2). This does not rule out the possibility that CO2 also drives temperature, and in theory a doubling of CO2 should cause about a 1 degree increase in temperature before any feedback effects are accounted, but feedbacks could be negative (dampening rather than amplifying temperature forcings), so there no reason, just from what we know about the greenhouse mechanism, that CO2 has to be a significant player. The one thing we can say is that whatever the warming effect of CO2, it is not detectable in the raw CO2 vs. temperature data.
This is in glaring contrast to solar activity, which lights up like a neon sign in the raw data. Literally dozens of studies finding .5 to .8 degrees of correlation with temperature. (-snip-). RF for CO2 is entered as ___ W/m^2 while RF for total solar effects is entered as ___ W/m^2. [I'm not going to quote the actual numbers, but yeah, the ratio is an astounding 40 to 1, up from 14 to 1 in AR4, which listed total solar forcing as 0.12 W/m^2, vs. 1.66 for CO2.]
So the 50% driver of global temperature according to mountains of temperature correlation data is assumed to have 1/40th the warming effect of something whose warming effect is not even discernable in the temperature record. (-snip-).
(-snip-)
Sabre, you did read the intermediate and advanced articles tabbed above, yes? Yes, global temp track solar variation quite well until about 1960. Where is it argued that it doesn't? What happens after 1960, as TSI drops from the modern max, and temp just keeps on rising. You're familiar with Pasini et al. (2012), yes? And the same Usoskin (2005) points out "during these last 30 years the solar total irradiance, solar UV irradiance and cosmic ray flux has not shown any significant secular trend, so that at least this most recent warming episode must have another source."
DSL,
Apparently some people don't feel uncomfortable commenting on posts they haven't read. It gets a bit ridiculous when the post you'd provide them with a link to in order to dispel their misconception is the one they've commented on!
Just out of curiosity, what's the most-commented post here at SkS? This would have to be a contender, which strikes me as amazing because it's one of the most obviously wrong myths yet apparently one of the most fervently argued.
Sabre @1045... Do you honestly believe that the broad scientific community hasn't already considered everything you've stated here before coming to the overwhelming conclusion that human are primarily responsibe for the rise of global temperature of the past 40 years?
Just curious.
JasonB... I was thinking exactly the same thing. Literally, this is probably THE most clearly debunked myths there is in the climate debate. It's stunning that anyone is still clinging to it.