3

Possible Duplicate:
Did the development of agriculture prevent an ice age occurring?

Some recent news reports about ancient anthropogenic methane emissions have hinted that the simultaneous contributions of the Roman Empire and the Han Chinese may have produced enough to start the human influence on climate two millennia earlier than the industrial revolution.

As the LA Times expresses it:

Until now, it was assumed by scientists that human activity began increasing greenhouse gas levels only after the year 1750.

Now, though, some think:

Centuries before the Industrial Revolution or the recognition of global warming, the ancient Roman and Chinese empires were already producing powerful greenhouse gases through their daily toil...

...The burning of plant matter to cook food, clear cropland and process metals released millions of tons of methane gas into the atmosphere each year during several periods of pre-industrial history

So, were ancient civilisations kick-starting warming 2000 years ago? Does the analysis of ancient emissions tell us anything about current warming?

Community
  • 1
matt_black
  • 56,186
  • 16
  • 175
  • 373
  • That story doesn't seem to have claim of "ancient civilisations kick-starting warming 2000 years ago". Do you have a source for that specific claim? If not, perhaps it would be better to remove it, and identify exactly which claim it is that you are sceptical of. – 410 gone Oct 05 '12 at 15:21
  • @EnergyNumbers The reason why the analysis of methane emissions made the news was that people have tended to assume that it wasn't until the *industrial revolution* that mankind made any contribution to warming. The essence of my question is whether that is wrong and some contribution started earlier. – matt_black Oct 05 '12 at 15:59
  • 2
    @matt_black What is it that you're actually skeptical of? I can tell you that the LA Times article is wrong when it says that scientists assume there was no contribution to GHG before 1750. – Tacroy Oct 05 '12 at 16:32
  • 1
    It looks like the claim to be sceptical of, is the LA Times' assertion that: "Until now, it was assumed by scientists that human activity began increasing greenhouse gas levels only after the year 1750.". There might be valid side-question either for physics.SE or chemistry.SE on whether Roman/Han cumulative emissions were enough to cause climate change at the time. – 410 gone Oct 05 '12 at 17:58
  • @Tacroy I'd accept a clear answer that summarised the amount and significance of Roman emissions and their impact on the climate. the LA Times is not alone in casually assuming warming started with the industrial revolution. – matt_black Oct 05 '12 at 19:20
  • 1
    @matt_black I'm still not sure I really get what the question is as it pertains to skeptics.stackexchange. Is it whether or not anthropogenic GHG emissions started before the Industrial Revolution? The answer is a very well supported yes, but I'm not sure a line in a LA Times article written by a journalist who probably knows very little about climate science counts as a "notable claim" that anthropogenic GHG emissions started with the Industrial Revolution. – Tacroy Oct 05 '12 at 19:40
  • @Tacroy I don't think the claim is unclear even if the LA Times doesn't illustrate it perfectly. The claim is *whether human activity made the world warmer before the industrial revolution.* – matt_black Oct 05 '12 at 20:32
  • 1
    @matt_black I guess I just don't think that this is a notable claim or appropriate for skeptics. Interesting, for sure, but wrong venue. – Tacroy Oct 05 '12 at 21:17
  • 3
    Very similar question: http://skeptics.stackexchange.com/questions/1801/did-the-development-of-agriculture-prevent-an-ice-age-occurring – Andrew Grimm Oct 05 '12 at 23:58
  • @AndrewGrimm: heh, I just had the same thought. This is a different paper with different particulars, obviously, but it does certainly seem to lend support to Ruddiman's hypothesis. – Jivlain Oct 06 '12 at 00:21
  • The only notable claim in this question is very well answered by the duplicate, and also this question is being flagged as off topic. – Sklivvz Oct 06 '12 at 21:22
  • @Sklivvz I can see the relationship to the AndrewGrimm question, but I though this was significantly more general so not a duplicate on the grounds that *preventing an ice age* is a lot more specific than *making the world a little warmer*. Also, I still have no clue why anyone (especially Tacroy) thinks this is off topic especially given the supposed duplicate. I hoped the questions would allow a more general response to a recent idea that has appeared widely in the media. – matt_black Oct 07 '12 at 13:56
  • @matt I don't think you are skeptical that the Romans used agricolture - but the greenhouse effect of agriculture is discussed [here](http://skeptics.stackexchange.com/q/41). I can't really see any added value over those two questions (but maybe I am just misunderstanding your intent!) – Sklivvz Oct 07 '12 at 14:12
  • @matt_black I don't think they're duplicates. This question asks specifically if the results of a new Nature paper are credible, whereas the other question asks if the hypothesis is supported. My understanding of skeptics.stackexchange is that it is for asking questions about unreferenced notable claims, and asking about the credibility of a Nature paper doesn't fit that description. Hence, it's off topic for skeptics. – Tacroy Oct 08 '12 at 17:47
  • @Tacroy The notable claim (romans warmed climate) is implicit in a lot of media reports so, I thought, deserved a skeptical response. The Nature paper would form *part* of the **answer** analysing whether the media interpretation is reasonable (I wasn't being skeptical of the Nature piece itself). It is also worth noting that the paper is rumoured to have had late edits to court the widespread media interpretation it eventual received. – matt_black Oct 09 '12 at 09:26
  • 1
    @matt_black: It's a matter of scale. Plants consume CO2 and produce O2. Animals (including humans) consume O2 and plants, and produce CO2. Humans contributed to this balance before they *were* humans. It got worse when we discovered how to make fire. It got worse when we discovered how to change wood- to farmland. It got worse when we discovered fossil fuels. The point being, it got worse **by orders of magnitude** with the start of the industrial revolution. Pointing to the Romans yelling "they did burn things as well" is a red herring. (Oh look, a squirrel.) – DevSolar Dec 19 '16 at 09:04

0 Answers0