Is anthropogenic global warming (AGW) theory or fact? Is there measured climate change on the other planets?

Question

Has AGW been proved to be fact? Explain why our sun can't be primarily responsible for our climate changes. Is a sun-based theory just too simple to be considered plausible? Have the other planets experienced corresponding climate change?

Answer 1

AGW proponents have tried to explain away warming on other planets with mechanisms already dismissed as causes for Earth's warming trend.  They've also shown solar luminescent output to not be a contributing factor...but fail to address other possible solar outputs (like UV and gravitational fluctuations).

AGW remains a theory.

Answer 2

It's a theory.  So are evolution and gravity.

Some planets have warmed recently.  Others have cooled.  Most plants+moons in our solar system are experiencing no significant temperature change.  But we don't need to look at other planets to see what's happening with the Sun.  We have satellites that observe solar output directly.

The Sun can't be responsible for the warming over the past 30 years because solar output has decreased over that period.

http://tinyurl.com/yprers

Consider the fact that no scientific study has ever attributed more than one-third of the warming over the past 30 years to the Sun, and most attribute just 0-10% to the Sun.

http://tinyurl.com/2ps4fy

Benjamin provided many good examples of such studies.

I don't see how anyone can argue the Sun is responsible when not one single scientific study has concluded that this could possibly be the case.

Answer 3

It's a guess.  No one can tell you if it will be warmer or cooler 5 years from now.

A toss of a coin is just as accurate as any guess.

Answer 4

AGW is unprovable with the enormous lack of data.  120 years of data out of 4 billion?

Weathermen can't get the weather right for tomorrow, 5 days from now, 2 months from now, 1 year from now.  What makes people think that a glorified weatherman (climatologist) can predict what's going on?

Answer 5

Evans - If only some of the planets are warming and the others are not, how can it be solar forcing?

Fact is, it's still theory, but it has been observed, just like gravity.  There is measured climate change on other planets, but that just means "change", not necessarily warming. Some are warming and some are cooling. But even those that are warming, Jupiter for example, are only warming at certain latitudes, which points to something other than solar forcing. It's normal.

I don't think anyone in their right mind would say the sun can't effect change. What scientists around the world are saying is that it's not the main factor NOW.

Answer 6

Climate change, whether it's human caused or not...happens.  We know this because of the fact that there used to be oceans and rainforests where there are other climates now.  This has been proven by archaeologists, not climatologists.  Also climate change on other planets.  Big probability...not proven.  Our latest photos from the martian surface show areas of erosion and areas that look like they were ancient oceans...but let's not forget that we once thought the moon was a disc and the world flat as a pancake.  Until we get physical data released detailing the sedimantary deposits on Mars, the idea that there were once vast oceans is merely hypothesis.

Answer 7

The "but half the planets in the solar system are warming, and Triton Too!" argument has been debunked so many times that I will not bother to do it here. If interested, here is the best debunking of them all:

http://tinyurl.com/2yjcqg

I think that it is funny that global warming deniers often point to climate change on other planets to deny that global warming is happening on this one. Also "warming on another planet would be an interesting coincidence but it would not necessarily have the same cause."

Given all of the recent studies published on solar output, it is amazing how many people still blame the recent global warming on the sun. The reality is that solar output (this includes electromagnetic energy from the entire spectrum, as well as cosmic rays) has not increased during recent decades. The following are excerpts from recent research on the link between recent global warming and solar activity (the first report linked is the most liberal):

Scafetta, 2006

"We estimate that the sun contributed as much as 45–50% of the 1900–2000 global warming, and 25–35% of the 1980–2000 global warming. These results, while confirming that anthropogenic-added climate forcing might have progressively played a dominant role in climate change during the last century.

http://www.fel.duke.edu/~scafetta/pdf/20...

Foukal, 2006

"The variations measured from spacecraft since 1978 are too small to have contributed appreciably to accelerated global warming over the past 30 years."

http://www.nature.com/nature/journal/v44...

http://www.mpa-garching.mpg.de/mpa/publi...

Foukal, 2006

"Our results imply that, over the past century, climate change due to human influences must far outweigh the effects of changes in the Sun's brightness. … Variations of this magnitude are too small to have contributed appreciably to the accelerated global warming observed since the mid-1970s, according to the study, and there is no sign of a net increase in brightness over the period."

http://www.ucar.edu/news/releases/2006/b...

Lockwood, 2007

"The analysis shows that global warming since 1985 has been caused neither by an increase in solar radiation nor by a decrease in the flux of galactic cosmic rays."

http://www.petedecarlo.com/files/448008a...

http://www.pubs.royalsoc.ac.uk/media/pro...

Lockwood, 2007

“There is considerable evidence for solar influence on the Earth’s pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.”

http://publishing.royalsociety.org/media...

Solanki, 2004

"Researchers at the MPS have shown that the Sun can be responsible for, at most, only a small part of the warming over the last 20-30 years. They took the measured and calculated variations in the solar brightness over the last 150 years and compared them to the temperature of the Earth. Although the changes in the two values tend to follow each other for roughly the first 120 years, the Earth’s temperature has risen dramatically in the last 30 years while the solar brightness has not appreciably increased in this time."

http://www.mpg.de/english/illustrationsD...

Ammann, 2007

“Although solar and volcanic effects appear to dominate most of the slow climate variations within the past thousand years, greenhouse gas effects have dominated the last century.”

http://www.aimes.ucar.edu/MEETINGS/2005_...

et. cetera

Other than the fact that such a hypothesis is not backed by observation, there are a few problems additional problems with the assumption that the majority of recent global warming is caused by the sun. (1) Most importantly, such an argument completely ignores the fact that the physics of increasing greenhouse gases concentrations can account for recent global warming.

(2) The warmest years in history, 1998, 2005, and 2007 have occurred near the "solar minimum" troughs of the 11-year solar cycle. Such an observation might suggest that the small increases in solar irradiance cannot be the main force that is driving recent global warming. The most liberal estimates of recent increases in solar irradiance is a smaller amount than the difference in irradiance between "solar maximum" and "solar minimum" of the 11-years solar cycle (0.1 %.)

(3) Increases in solar activity should warm the entire atmosphere, right? Cooling in the lower stratosphere has been observed during recent decades.

Answer 8

the short answer is--a theory.