Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Donate

Twitter Facebook YouTube Pinterest

RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
Keep me logged in
New? Register here
Forgot your password?

Latest Posts

Archives

CO2 limits will make little difference

What the science says...

While it's true that any single country's CO2 emissions reductions will make little difference, only if every nation agrees to limit CO2 emissions can we achieve significant cuts on a global scale.

Climate Myth...

CO2 limits will make little difference
"Cap and tax is as pointless as it is cruel. Australia accounts for 1.5 per cent of global carbon emissions. So if it cut its emissions, the warming forestalled would be infinitesimal." (Christopher Monckton)

Some skeptics have claimed that anything more than a modest greenhouse gas emissions reduction would shut a nation's economy down.  However, as we previously explored, this claim is not even remotely true.  In fact, we showed that the benefits of carbon pricing would outweigh the costs several times over, even in the legislation proposed in the USA which would have cut the country's emissions 80% by 2050.

Australian Example

If Australia were to cut its emissions at a constant rate to get to 80% lower emissions by 2050, then it would have emitted 40% less CO2 by 2050 than it would have done at today's rates.  In a business-as-usual scenario, the atmospheric CO2 concentration in 2050 will be approximately 550 parts per million by volume (ppmv).  Australian CO2 emissions are approximately 1.5% of global emissions, so if the country were to maintain this percentage until 2050, Australia would be responsible for 1.5% of the 160 ppmv increase during that period, or 2.4 ppmv.  If Australia were to cut its emissions by an average of 40% over that period, the difference in atmospheric CO2 concentration would be approximately 1 ppmv.

So the skeptics seemingly have a point here.  CO2 emissions cuts from Australia, by itself, would have an insignificant effect on global CO2 concentrations and temperature.  However, this is a perfect example of what's known as the Tragedy of the Commons.

Tragedy of the Commons

The Tragedy of the Commons was first described by Hardin (1968).  It's "a dilemma arising from the situation in which multiple individuals, acting independently and rationally consulting their own self-interest, will ultimately deplete a shared limited resource even when it is clear that it is not in anyone's long-term interest for this to happen."

The global climate is effectively a shared natural resource.  If every nation decides to continue emitting CO2 unabated in their own self-interest, the consequent climate change will be bad for almost everyone.

Game Theory

The concept of Nash equilibrium in game theory provides an analogous scenario.  In our example we'll consider the USA and Australia, each with $10.  Reducing carbon emissions will cost either country $3.  The consequences of global warming will cost each country $7 if no action is taken, and $4 if only one takes action.  The potential resulting outcomes look like this (remaining funds for USA in blue, and for Australia in red):

 

 

Australia

 

 

Emissions Reduced?

Yes

No

USA

Yes

7, 7

3, 6

No

6, 3

3, 3

Either side can only tie or win if they don't reduce emissions, and they can only tie or lose if they do reduce emissions.  Thus it seems to be in each country's best interest not to reduce emissions.  But the best overall outcome is if both sides reduce their emissions, in which case the net economic impact is smallest.  If each country looks out only for its own best interest, the overall economic impact is largest.

It's quite a good analogy to carbon pricing.  A frequent argument used by politicians in most countries is "if our country introduces carbon pricing, businesses will just move to another country where they can emit carbon for free".

So how do you get both sides to reduce their emissions even though it seems to be in the best interest of neither?  Collusion. 

International Climate Conferences

This is the purpose of international climate conferences such as those held at Kyoto and Copenhagen.  Every nation can make the argument that their emissions cuts alone will have an insignificant impact on global temperatures.  We've heard the exact same argument in the USA, despite our much larger overall emissions than Australia.

But if all nations can come together and agree to reduce CO2 emissions in their own best interests, then the combined emissions reductions and impact on global temperatures can be significant.  But to achieve the necessary global emissions reductions to avoid dangerous global warming, we need all countries on board.

Last updated on 1 March 2011 by dana1981.

Printable Version  |  Offline PDF Version  |  Link to this page

Comments

Comments 1 to 6:

  1. the whole post is just mixing up three different notions

    * reduction of energy intensity
    * reduction of annual rate of global emissions
    * reduction of total emission integrated over the century.

    so in the example of Nash equilibrium, one should first careful define which of the previous "reduction" it addresses. In my opinion, the constant failure of international discussions about "reduction" is simply due to the fact that this is never well defined.
  2. So if there is no agreement at a conference, then there is no point in going it alone in say Australia?
  3. Mods, is Faramir the same person as Dorlomin?
  4. Without wanting to overcomplicate the point, I would say that:

    a) it's overstating things to say that CO2 limits by all countries are needed; a large number of countries emit very little due to small size, poverty or both. A suitable agreement between the top 20 emitters would cover most global emissions and most of world trade. Adding further parties is useful for reducing trade distortions and adding a bit more abatement potential, but balanced against this is the difficulty of making progress in full multilateral forums with 190+ parties.

    b) An agreement/set of agreements need not be through the current UN process; while this is looking healthier post-Cancun and post-Durban than just after Copenhagen, it remains a very difficult process. Other tracks can be (and to a significant extent are being) pursued as well, including unilateral national/regional policies (California, Australia, EU), bilateral agreements (Australia/Indonesia discussions for example) and smaller multilateral groupings (Major Economies Forum eg). The 'success' or 'failure' of a particular UNFCCC conference/process remains important, but it is far from the whole story.
  5. Came to this page via the Christy Crocks page. When I click on any link in the Climate Myths column for April 1,2011 I receive the following error message:

    Media Player
    You are not authorized to view this resource.


    I have received the exact same message in regards source links in the Lindzen Illusions. I am using Windows 7 with Firefox as a browser.
  6. I followed this link from the Spencer slip ups page. This doesn't seem to rebut Spencer's point that even massive reductions in CO2 output will only marginally decrease warming. Is there a link to a more direct rebuttal?

Post a Comment

Political, off-topic or ad hominem comments will be deleted. Comments Policy...

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

Link to this page



The Consensus Project Website

TEXTBOOK

THE ESCALATOR

(free to republish)

THE DEBUNKING HANDBOOK

BOOK NOW AVAILABLE

The Scientific Guide to
Global Warming Skepticism

Smartphone Apps

iPhone
Android
Nokia

© Copyright 2014 John Cook
Home | Links | Translations | About Us | Contact Us