Climate Science Glossary

Term Lookup

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


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


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 Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube 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...

New? Register here
Forgot your password?

Latest Posts


Earth Overshoot Day

Posted on 13 August 2015 by Guest Author

In less than 8 Months, Humanity exhausts Earth's budget for the year

Earth Overshoot Day 2015 lands on August 13. Please see the new website for Earth Overshoot Day at

Below is information from Earth Overshoot Day 2014:

August 19 is Earth Overshoot Day 2014, marking the date when humanity has exhausted nature’s budget for the year. For the rest of the year, we will maintain our ecological deficit by drawing down local resource stocks and accumulating carbon dioxide in the atmosphere. We will be operating in overshoot.

Just as a bank statement tracks income against expenditures, Global Footprint Network measures humanity’s demand for and supply of natural resources and ecological services. And the data is sobering. Global Footprint Network estimates that approximately every eight months, we demand more renewable resources and C02 sequestration than what the planet can provide for an entire year.

Read our 2014 press release in your language:

Click here to learn more about Earth Overshoot Day, and how it has changed over time.

Click here for an economics-focused press release on 2014 Earth Overshoot Day.

Click here for media coverage of Earth Overshoot Day 2014.

Earth Overshoot Day is the annual marker of when we begin living beyond our means in a given year. While only a rough estimate of time and resource trends, Earth Overshoot Day is as close as science can be to measuring the gap between our demand for ecological resources and services, and how much the planet can provide.


The Cost of Ecological Overspending

Throughout most of history, humanity has used nature’s resources to build cities and roads, to provide food and create products, and to absorb our carbon dioxide at a rate that was well within Earth’s budget. But in the mid-1970s, we crossed a critical threshold: Human consumption began outstripping what the planet could reproduce.

According to Global Footprint Network’s calculations, our demand for renewable ecological resources and the services they provide is now equivalent to that of more than 1.5 Earths. The data shows us on track to require the resources of two planets well before mid-century.

The fact that we are using, or “spending,” our natural capital faster than it can replenish is similar to having expenditures that continuously exceed income. In planetary terms, the costs of our ecological overspending are becoming more evident by the day. Climate change—a result of greenhouse gases being emitted faster than they can be absorbed by forests and oceans—is the most obvious and arguably pressing result. But there are others—shrinking forests, species loss, fisheries collapse, higher commodity prices and civil unrest, to name a few. The environmental and economic crises we are experiencing are symptoms of looming catastrophe. Humanity is simply using more than what the planet can provide.



Methodology and Projections

Earth Overshoot Day is an estimate, not an exact date. It’s not possible to determine with 100 percent accuracy the day we bust our ecological budget. Adjustments of the date that we go into overshoot are due to revised calculations, not ecological advances on the part of humanity.

As Global Footprint Network methodology changes, projections will continue to shift. But every scientific model used to account for human demand and nature’s supply shows a consistent trend: We are well over budget, and that debt is compounding. It is an ecological debt, and the interest we are paying on that mounting debt—food shortages, soil erosion, and the build-up of CO? in our atmosphere—comes with devastating human and monetary costs.


Calculate your own personal Ecological Footprint and learn what you can do to reduce it with ourFootprint Calculator.

0 0

Printable Version  |  Link to this page


Comments 1 to 7:

  1. It seems to me that, with regard to some resources such as maintaining a safe level of CO2 in the atmosphere and oceans, every country in the world starts off in a state of deficit on January 1 of each year.

    0 0
  2. Joel_Huberman @1, absent all anthropogenic emissions, the total CO2 content in the atmosphere would decline to about 310 ppmv over about 200 years.  The total forcing for 310 ppmv is about 0.55 W/m^2, with an expected equilibrium temperature response of about 0.42 C above preindustrial levels.  That is, the equilibrium temperatures will be equivalent to those in the 1960s, and can reasonably be supposed to be "safe" - indeed, may even be beneficial relative to pre-industrial levels.  Ergo, over the life time of any reasonable policy projection, restricting emissions to approximately 5% of current levels could be considered sustainable.  That being the case, the following nations can reasonably be supposed to never exceed their sustainable emissions levels (the numbers being their ranking in world per capita emissions):

    178. Bangladesh
    179. Cambodia
    180. Cameroon
    181. IvoryCoast
    182. Kenya
    183. Kiribati
    184. Laos
    185. Burma
    186. Sudan
    187. Comoros
    188. Gambia
    189. Guinea-Bissau
    190. Haiti
    191. Liberia
    192. SierraLeone
    193. Timor-Leste
    194. Togo
    195. Zambia
    196. BurkinaFaso
    197. CentralAfricanRepublic
    198. Eritrea
    199. Ethiopia
    200. Guinea
    201. Madagascar
    202. Malawi
    203. Mozambique
    204. Nepal
    205. Niger
    206. Rwanda
    207. Somalia
    208. Uganda
    209. Tanzania
    210. Afghanistan
    211. Burundi
    212. Chad
    213. DemocraticRepublicoftheCongo
    214. Mali

    So, granted that the world's worst emitter exceeds its sustainable emissions in less than two days, and the world average exceeds sustainable emissions before the end of January, I do not think it is fair to say that all nations begin the year with a deficit.


    0 0
  3.  Interesting.

     Quantitative argument is where it's at and the politicians can only defend bias in the speakers chair for so long until the pertinent figures reveal themselves to the majority of voters and action is voted for!!

    0 0
  4. Tom Curtis @ 2. Thanks for your interesting response. I wasn't thinking about emissions per country, but global emissions, and I was thinking about the fact that atmospheric CO2 is currently about 400 ppm, way above sustainable levels of 350 ppm (according to Hansen and or 310 ppm (according to your analysis). Thus the Earth as a whole is already way over budget. Consequently, even Mali could contribute to bringing the Earth back to a reasonable carbon budget by reducing its miniscule CO2 emissions even further.

    0 0
  5. Joel_Huberman @4, I made no analysis of the 'sustainable level' of CO2 in the atmosphere.  That is because, given sufficient time adapt, any level of CO2 under 1000-2000 ppmv is 'sustainable'; while any level above 280 ppmv will require some adaption.  Consequently the idea of a sustainable level of CO2 is not particularly coherent.  However, if we are going to use the concept, 310 ppmv is a level that will require minimum adaption by either nature or humanity and can reasonably be claimed to be sustainable.  However, for policy purposes, a peak level of 450 ppmv (+/- 100 ppmv) represents the consensus value for a CO2 level to which human society could reasonably adapt and and live with on a sustained basis.  At least, that is how I understand the IPCC position.

    More importantly for my argument @2 above, the assumed emission levels are those at which CO2 concentrations will fall over time (due to further take up of CO2 by the ocean, and ocean buffering by erosion) so that if we reduced emissions to about 5% of current global emissions now (immediately) emissions would fall over the medium term and stabilize in the low 300's of ppmv.  We would not further need to enhance that rate of natural fall by sequestration and geoengineering (although it might still be desirable to do so).  (Note that ocean buffering will also restore ocean pH levels, but only over a time line of a thousand years or so.)

    If, as is certain, we increase CO2 levels above the current 400 ppmv, we will also need to reduce the sustained emissions to allow for the natural reduction in CO2 level to bring us to a sustainable long term atmospheric concentration.  If we continue increasing atmospheric concentration until 2050 (virtually certain), the sustainable level drops down to zero emissions; and beyond that we will need active geosequestration.  But if all nations had per capita emissions equivalent to those on the list above, global warming would be a problem that would solve itself with some minor ecological and economic adaption.  Ergo, that level, or thereabouts, represents the current sustainable level of emissions.

    That the sustainable level of emissions will fall due to the activities of other nations is not the fault of the nations currently emitting at levels that are currently sustainable.

    0 0
  6. The real Debt and Deficit Disaster.

    0 0
  7. There is one physical property of CO2 that is not talked about and that is its weight.

    It weights more that air and sinks in air that's why 3 ski patrollers died at Mammoth,CA and in Yellowstone animals are killed there because the CO2 is heavier that air.

    In fact, nature O2/CO2 cycle is built around this property. The green leaves, at ground level (where CO2 sinks to), take in CO2 and produce O2. Think of it differently_____NO CO2-------NO O2!

    I'm not saying we are not the cause, but I think in another way.

    Carbon is the cause, yes. Fine particles of carbon can float in air. That is the cause of many a coal mine explosion. So CO2 sinks in air but C can float in air if the particle size is right.

    And what would produce CO2 in the upper atmosphere? Since CO2 can not float up to there!

    Highly reactive ozone O3 (produced by UV from the sun) and carbon particles, C+O3 = CO2+O, and then the CO2 sinks down. They also say there is an ozone depletion problem allowing more UV in!

    John S Goldner

    0 0
    Moderator Response:

    [PS] Offtopic. Please immediately familiarize yourself with the  Comments Policy. Conformance is not optional. Ensure future comments are in full compliance with it.  Thanks for your understanding and compliance in this matter.

    And you might want to familiarize yourself with the science and observations of gas distributions in the atmosphere once a gas has been become mixed.

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

The Consensus Project Website


(free to republish)

© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us