Did any natural warming occur without greenhouse gas involvement?

Question

I'm trying to understand the "There were natural cycles in the past" argument, since those natural cycles provide key evidence that scientists point to, confirming that greenhouse gases can (and have) warmed the planet.

For example, in a "best anwser" this article was offered as if it showed non-CO2 causes, but it clearly notes CO2's importance:

Sun's Magnetic Activity Varies In 100,000-Year Cycles

http://www.unisci.com/stories/20022/0606022.htm

"...regarding the current global warming debate, it still needs to be examined if the role of solar activity will exacerbate the rising temperatures that result from carbon dioxide buildup in the atmosphere."

Show me even 1 warming without carbon dioxide or methane! That should be easy. Would one such event could cancel out all of the examples where they were involved? Of course not.

So why do people think that "Natural cycles happened in the past" challenges greenhouse gas theory in some way, when they are the evidence for it?

Answer 1

there is only the very gradual, steady increase in the suns activity over the lifetime of the planet.

"The energy input to Gaia has been gradually increasing

(ca. 1% every hundred million years) as the Sun becomes more luminous

with time. Variations in the Earth’s orbital parameters

also alter the total energy input and its distribution

across the Earth’s surface on time-scales of 1000–100 000 years."

Lenton and van Oijen ; Gaia as a complex adaptive system (2002)

http://www.pubmedcentral.nih.gov/picrend...

Answer 2

Really it's just a bit of confusion on the parts of "skeptics."  The '800 year lag' argument ignores the fact that for thousands of years after the initial lag, CO2 was the driving force behind global temperature change.

What the 'skeptics' should be trying to argue is not that CO2 can't cause warming - which is an absolutely ludicrous argument which ignores the basic physics of the greenhouse effect - but that CO2 can't *initiate* warming.

Of course, physically speaking the latter argument isn't any less ludicrous than the former, but at least it would fit the data.  Most of the time CO2 doesn't initiate warming, but it does eventually cause warming.  That of course doesn't mean that it can't initiate warming (just because I've never jumped through a flaming hoop doesn't mean I can't do it under the appropriate conditions), but at least it would be a mostly historically accurate argument.

The problem with "skeptics" is that not only do they ignore or misunderstand basic physics, but they even get their wrong arguments wrong.

Answer 3

There are natural sources of environmental pollution as well as man made. 20 yrs. ago the prediction was that we were going into another ice age. Prehistoric warming and cooling of our planet have happened since the beginning of time and before humans existed. Evidence is shown in fossils geology. The rings of ancient trees like the redwoods show thinning and thickening of the rings indicating changes in the climate and amount of water at a given time. Volcanoes give off a lot of pollution. No, we don't really have enough info to pin it down to one thing or another and maybe we never will.

Answer 4

The temperature effect of atmospheric carbon dioxide is logarithmic, not exponential.

The potential planetary warming from a doubling of atmospheric carbon dioxide from pre-Industrial Revolution levels of ~280ppmv to 560ppmv (possible some time later this century - perhaps) is generally estimated at around 1 °C.

The guesses of significantly larger warming are dependent on "feedback" (supplementary) mechanisms programmed into climate models. The existence of these "feedback" mechanisms is uncertain and the cumulative sign of which is unknown (they may add to warming from increased atmospheric carbon dioxide or, equally likely, might suppress it).

The total warming since measurements have been attempted is thought to be about 0.6 degrees Centigrade. At least half of the estimated temperature increment occurred before 1950, prior to significant change in atmospheric carbon dioxide levels. Assuming the unlikely case that all the natural drivers of planetary temperature change ceased to operate at the time of measured atmospheric change then a 30% increment in atmospheric carbon dioxide caused about one-third of one degree temperature increment since and thus provides empirical support for less than one degree increment due to a doubling of atmospheric carbon dioxide.

There is no linear relationship between atmospheric carbon dioxide change and global mean temperature or global mean temperature trend -- global mean temperature has both risen and fallen during the period atmospheric carbon dioxide has been rising.

The natural world has tolerated greater than one-degree fluctuations in mean temperature during the relatively recent past and thus current changes are within the range of natural variation. (See, for example, ice core and sea surface temperature reconstructions.)

Other anthropogenic effects are vastly more important, at least on local and regional scales.

Fixation on atmospheric carbon dioxide is a distraction from these more important anthropogenic effects.

Despite attempts to label atmospheric carbon dioxide a "pollutant" it is, in fact, an essential trace gas, the increasing abundance of which is a bonus for the bulk of the biosphere.

There is no reason to believe that slightly lower temperatures are somehow preferable to slightly higher temperatures - there is no known "optimal" nor any known means of knowingly and predictably adjusting some sort of planetary thermostat.

Fluctuations in atmospheric carbon dioxide are of little relevance in the short to medium term (although should levels fall too low it could prove problematic in the longer-term).

Activists and zealots constantly shrilling over atmospheric carbon dioxide are misdirecting attention and effort from real and potentially addressable local, regional and planetary problems.

J.S.  I am not claiming they were no CO2 emissions before 1950 we both know that,  and I agree that most scientist are not  zealot however we both have to  realize there are zealots.  And I am with you 100% on the tax scheme.  I have learned that your correct on the name calling so I will stick to the debate.   I want you to understand that my family and I are for the environment I want the country to progress and transition without hurting the working class.

Answer 5

We can only theorize at this moment in time.  I think Global Warming (GW)  is partly our fault due to the gases we as a People are pumping into the atmosphere.  I think we should be concerned not because of the possible not probable effects but because of rising fuel costs.  The sooner we become energy efficient, the more we can depend upon ourselves and not Saudi Arabia.  The real cause of GW are lightning strikes causing huge forest fires, earthquakes and volcanoes and tiday waves releasing tons of methane into the atmosphere.

Answer 6

the earth started warming a while ago before people were polluting the earth to stop the advancement of glaciers

Answer 7

No, it's physically impossible.  Greenhouse gases HAVE to warm the planet.

And, since warmer air can hold more water vapor, water vapor HAS to be a positive feedback, for as long back as we had significant amounts of liquid water.

To claim that these things are unimportant is simply ridiculous.

In past times changes in solar radiation were as important as greenhouse gases or even more.  There's no theoretical reason that can't happen.

But we know it's not happening now, because we measure the Sun.

"Recent oppositely directed trends in solar

climate forcings and the global mean surface

air temperature", Lockwood and Frolich (2007), Proc. R. Soc. A

doi:10.1098/rspa.2007.1880

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

News article at:

http://news.bbc.co.uk/1/hi/uk/6290228.st...

Answer 8

200,000 years ago.about 1/3 the earth was under ice...except for the " little ice age" in the 1600s the earth has been warming without mans help;

Answer 9

ya man