If humans aren't the primary cause of the current global warming, what is?

Question

In a previous question I asked skeptics if they think the man-made global warming theory isn't the most likely explanation for the current warming, what is?

They answered "you used Wikipedia I hate liberals blah blah blah". None have yet provided a plausible alternative theory.

We know it's not the Earth's natural cycles, because we're in a stable and cooling cycle right now.

http://www.sciencemag.org/cgi/content/summary/297/5585/1287

Solar output has decreased over the past 30 years as global warming has accelerated rapidly

http://publishing.royalsociety.org/media/proceedings_a/rspa20071880.pdf

and even solar physicists don't think the Sun is the main cause of the current warming

http://solar-center.stanford.edu/sun-on-earth/glob-warm.htm

The galactic cosmic ray theory has many fundamental problems.

http://www.realclimate.org/index.php/archives/2007/10/cosmic-rays-don%e2%80%99t-die-so-easily/

So if not humans, what's the cause of the current warming?

Bear in mind that your theory should be able to explain the facts like the Earth is warming more at night than during the day, and the upper atmosphere is cooling.

Answer 1

Natural cycles (Milankovitch cycles) partially explain past warming and cooling trends but fail to fully explain many of them without additional influences such as greenhouse gasses. Here are some of the problems associated with solar/orbital cycles being a sole factor:

http://en.wikipedia.org/wiki/Milankovitch_cycles#Problems

Involvement of greenhouse gasses in the carbon cycle helps fill in the holes in solar cycle theory. If there's another scientific explanation, I haven't seen it.

An often-cited 1980 study by Imbrie and Imbrie determined that "Ignoring anthropogenic and other possible sources of variation acting at frequencies higher than one cycle per 19,000 years, this model predicts that the long-term cooling trend which began some 6,000 years ago will continue for the next 23,000 years." More recent work by Berger and Loutre suggests that the current warm climate may last another 50,000 years.

The key words here are "Ignoring anthropogenic sources." In other words, we can claim that we're in a cooling trend, if you ignore mankind's influence, and ignore the current warming. A common misleading version drops the first half of the quote as if to say that we're in a cooling trend. Cooling is what a natural solar cycle theory would predict, which is exactly why the current observed warming needs scientific explanation.

It's revealing that there don't seem to be many science-supported answers to your question that better explain the issues with simple solar (Milankovitch) cycle theory, including both past and current warming.

EDIT -

The 2007 Lockwood / Froehlich paper link below specifically contradicts the one outlying Svensmark paper referenced. Hansen also refutes solar radiation.

If McKitrick is porposed as credible, I'd want a clear explanation of why he is a Senior Fellow at the the Exxon-funded Frasier Institute, and why he publishes papers with a strategic advisor to oil and gas exploration company CGX Energy (McIntyre) and with a senior fellow at the oil industry-funded Cato Institute (Michaels).

Another skeptical scientist Douglass writes papers with S. Fred Singer, who founded the Science and Environmental Policy Project in 1990. In a February 2001 letter to the Washington Post, Singer denied receiving funding from the oil industry, except for consulting work some 20 years prior. SEPP, however, received multiple grants from ExxonMobil, including 1998 and 2000:
http://www.exxonsecrets.org/html/orgfactsheet.php?id=65

Gray may have a point that there may not be enough hurricane season data points to draw conclusions, but high hurricane counts and intense hurricanes would be a weather symptom, and are not inovled in the core carbon cycle climate science. In other words, it's intersting that he is skeptical, but his specialty does not seem to make him qualified to comment on global climate. His skepticism was considered (and Lindzen, McKitrick, etc) in the consensus opinion. Note that contrary to what the special interests say about consensus, the meaning of consensus implies disagreement, and that process of considering opposing views is what makes the consensus-building process valuable. Gray et al are not alone; just as many (if not more) scientists were disappointed that their more pessimistic opinions were not included in the final IPCC consensus report.

I agree with people who criticize Al Gore's movie; the personal agenda included and some of its more strident moments both do a disservice to science. If it encourages people to look into the issue, great. Its faults however don't reflect anything about the science that it purports to cover.

Answer 2

The fact that the earth has gone through major climate changes in the past demonstrates that it is possible for the earths change in climate significantly and at a rapid rate without any human interference.

In the IPCC's latest report they talk about changes to external warmings taking several centuries to reach equalibrium (not years). The papers which talk about the short term reduction in solar radiance only conclude that recent trends are in the opposite direction to recent global temperature changes, but the time scales involved prevent any definite conclusions. It's like saying I turned down my thermostat slightly a few seconds ago, so I know my furnace isn't heating anymore.

If these things that you claim about reduced diurnal temperature range and upper atmosphere cooling consistent with greenhouse effect are true, the the IPCC hasn't got around to included them in their concensus yet. The fact that they haven't suggest that the science isn't convincing.

Answer 3

I'll go with Solar System Physicist and Senior Scientist at the Danish National Space Center, Heinrick Svensmark.

http://www.spacecenter.dk/research/sun-climate/Scientific%20work%20and%20publications/resolveuid/86c49eb9229b3a7478e8d12407643bed

Answer 4

Many scientists, including myself, would disagree with the conclusion that solar activity is not the primary driver behind increased temperatures. The Royal Society paper referenced is hardly authoritative, and certainly not conclusive. Read by a trained eye, it's hard to see how Lockwood and Frolich came to any conclusion at all, much less the conclusion they did.

The climate is influenced by a variety of factors. Carbon dioxide (and other greenhouse gases) play a relatively minor role in determining temperature. What scientists argue about, in terms of global warming, is whether that effect is teeny or merely weeny.

The recent study released by the Journal of Climatology (Douglass, et. al.) suggests that the models that blame global warming on human activity are wrong (based on actual, observed data). http://www3.interscience.wiley.com/cgi-bin/abstract/117857349/ABSTRACT?CRETRY=1&SRETRY=0

The High Court in Britain also recently ruled that "An Inconvenient Truth" is chock full of factual errors and hyperbole, (which any legitimate scientist would admit). http://business.timesonline.co.uk/tol/business/law/corporate_law/article2633838.ece

Do we know the cause of recent climate change? Not conclusively. Not yet. But this leads to a bigger question. If it's NOT human activity causing global warming, clearly we should be preparing for a change we can not control, instead of wasting time and resources on fixing something that's not broke. In that scenario, what do we?

My own E-Z to understand, and entertaining, take on global warming can be found in a slideshow here: http://trzupek.wordpress.com/global-warming-lite-slideshow/

“A categorical summary statement like this (that humans are causing climate change) is not supported by the evidence in the IPCC WG I report. Evidence shown in the report suggests that other factors play a major role in climate change, and the specific effects expected from greenhouse gases have not been observed.” Dr. Ross McKitrick, Member, International Panel on Climate Change (IPCC)

“The text of the IPCC report shows that this is decided by a guess from persons with a conflict of interest, not from a tested model.” Dr. Vincent Gray, Member, International Panel on Climate Change

Answer 5

In the morning, if the sky is clear, look up. That really bright spot in the sky... well it's called the sun. It has some effect on what happens here. When you discover that all the planets in the solar system are warming (i.e. the polar ice caps on Mars are melting) and man is not there, then you start to look at something else that they have in common, like the sun, as the possible source.

Answer 6

These are the same "Climate Experts" than can't even predict what the weather will be like in 14 days. These are the same types who said there was no such thing as the Lowland Gorilla, that the Coelacanth was extinct for over 6 million years, that we were headed for an Ice Age in the 70's, that there was going to be a Swine Flu (and now a Bird flu) pandemic etc.....

I've pointed this out before, the simplest explaination is almost always the most correct one. This is part of a natural weather cycle. Of course for you conspiracy buffs it's always easier to blame mankind for everything you don't like. Just remembering my Geology classes that pointed out when Mt Pinatubo errupted in 1991 it expelled more greenhouse gasses into the air in two weeks than mankind has done in 5,000 years same with Mt St Helens. So spare us the chicken little science that has yet to be proven to an acceptable standard.

Answer 7

In regard to one of the previous answers: surely the theory of glacial cycles being predominantly controlled by Milankovitch Cycles (changes in the parameters of earths orbit) along with the effects of feedback systems like ice sheet area and atmospheric CO2 concentration provide an adequate explanation for glacial change over at least the last million years?

Of course there is still plenty of work to be done given the huge complexities of studying climate and weather patterns but to play down climate change because the cause of past climatic changes are not 'fully' understood seems rather disingenuous what with the compelling nature of the Milankovitch theory. (If you are familiar with such theories, please remember that other users may not be and to imply that there are no explanations for past climate change is misleading)

Answer 8

Climate scientists still have not figured out for sure what causes ice ages. Most of North America was covered by glaciers 20,000 years ago and those melted about 10,000 years go. Nobody knows why. So I would question anyone who claims to know for sure why the climate is warming now. It is plausible that the added CO2 is the cause, or part of the cause, but until they can prove for sure what causes the ice age cycles, I am skeptical of any claims they they know what is going on now and what will happen in the future.

Answer 9

It is obvious to me that if we were cooling you would ask the exact same question substituting cooling for warming and your underlying point would be to blame humans for the cooling, especially western free markets, petroleum use, and industry. The cause of attacking capitalism never changes. The only thing that changes are the particular scare tactics deployed.

Answer 10

"If recent warm periods (or interglacials) are a guide, then we may soon slip into another glacial period. But Berger and Loutre argue in their Perspective that with or without human perturbations, the current warm climate may last another 50,000 years". This quote is from your first link. I though Global Warming was going to kill everyone and destroy the earth imminently? Now 50,000 years? What is it? Please get your stories, fables and tales straight.