The Arithmetic of Global Warming

Anita L. Wenden - August, 2013

Creating Sustainable Communities

Anita Wenden is President and co-founder of Earth and Peace Education International (EPE), for which she  develops and organizes EPE’s educational programs. She has taught at the UN mandated University for Peace (Costa Rica) and with the online program in Peace and Conflict Studies, Sydney University .  She is co-founder and book review editor of the Journal of Peace Education  and professor emerita at York College, City University of New York. 

As is now recognized by the Intergovernmental Panel on Climate Change (IPCC)* and noted climate scientists,  the increasing level of greenhouse gases (GHGs)  in the  atmosphere due to human action will lead to fundamental physical changes in the Earth’s life support systems, i.e. the atmosphere (air), hydrosphere (water) and lithosphere (ground/rocks).

Bill McGibben (2012) makes explicit the seriousness of this threat to ecological security using the arithmetical analysis first published by financial analysts in the U.K. He points to the differences in perspective between limits on the increase of GHG’s posed by science and the practices of the world’s economies with three simple numbers.

The First Number: 2° Celsius

Written into Paragraph 1 of the Copenhagen Accord, the outcome document of the Copenhagen Global Climate Conference 2009, and now the official position of 167 countries who signed on to the Accord, Planet Earth’s temperature should not be allowed to rise beyond 2 degrees Celsius or 3.6 degrees Fahrenheit if we want to avoid the destructive consequences of a heated Earth.  However, based on the damage caused by only the .8 degree rise in temperature we are now experiencing, many scientists believe that two degrees is an inadequate target. McGibben (2012) quotes:

(1) Kerry Emanuel of MIT, a leading authority on hurricanes who writes "Any number much above one degree involves a gamble,….and the odds become less and less favorable as the temperature goes up.”

(2) Thomas Lovejoy, once the World Bank's chief biodiversity adviser, who agrees that,  "If we're seeing what we're seeing today at 0.8 degrees Celsius, two degrees is simply too much. "

(3) NASA scientist James Hansen, the planet's most prominent climatologist, who refers to the 2 degree target as “a prescription for long-term disaster."

Despite these misgivings, McGibben adds that politics won over scientific data, and the world settled on the two-degree target.

The Second Number: 565 Gigatons 

565 gigatons refers to Planet Earth’s carbon budget, i.e. the amount of carbon that can safely be poured into the atmosphere by midcentury and no sooner by burning gas, coal and oil if Earth is to remain below 2 degrees Celsius.
This is a number confirmed by multiple computer simulations, However, a study of the carbon output of the world’s economies predicts  that carbon emissions will keep growing by roughly three percent a year and at that rate, blow through our 565-gigaton allowance in 16 years, 34 years before the midcentury deadline.

The Third Number: 2,795 Gigatons  

2795 gigatons refers to the fossil fuel we're currently planning to burn. It is the amount of carbon already contained in the proven coal and oil and gas reserves of the fossil-fuel companies, and the countries, e.g. Venezuela or Kuwait,  that act like fossil-fuel companies.

The key point is that 2,795 is five times higher than 565, the extent of our carbon budget. In other words. locked away underground, we have five times as much oil and coal and gas on the books as climate scientists think is safe to burn.  And while, this coal and gas and oil is still technically in the soil, it's already above ground economically. It's figured into share prices, companies are borrowing money against it, nations are basing their budgets on the presumed returns from their patrimony.

The threat these numbers augur for ecological security is already manifest.  McGibben (2012) gives examples of the following impacts on Earth’s life support systems:

the hydrosphere:  A third of summer sea ice in the Arctic is gone and the oceans are 30 percent more acidic

the atmosphere: The atmosphere over the oceans is a shocking five percent wetter, loading the dice for devastating floods; May 2012 was the warmest on record for the Northern Hemisphere:; the same month Saudi authorities reported that it had rained in Mecca despite a temperature of 109 degrees, the hottest downpour in the planet's history.

the lithosphere: The United States National Resources Defense Council www.nrdc,org/health/climate/drought.asp reports that climate change will lead to drought, endangering water quality with serious consequences for commercial agriculture and food security. According to a spokesman for small island nations, additional warming will cause some countries to disappear, e.g. the Maldives.

In the very long term, if warming reaches what is referred to as the tipping point, i.e. the point which triggers irreversible changes with large scale adverse consequences, e.g. the Arctic summer sea ice could completely disappear; the circulation of major Atlantic Ocean currents could risk shutdown and cooling of Europe; the Amazon rainforest could risk collapse due to warming and reduction of rainfall. (McGibben 2012, UK Ministry of Defence, 2008) 

What are the implications of these numbers for community sustainability?

Contextual sustainability, the organizing principle basic to EPE’s educational approach, maintains that the Earth is the primary context and essential foundation of all social activity.  Damage to Earth’s integrity, namely her life support systems, therefore, will also impact upon the quality of life of sustainable communities. 

Of course, McGibben’s numbers are global in scope and somewhat abstract as is the principle of contextual sustainability. Therefore, what this implies for the quality of life and ecological sustainability of local communities may  not be so clear unless readers take up our concluding offer to consider the following questions as they apply to communities in their bio-region** in the present and the future.

1) How has the availability and quality of the local water supply been affected up to now ?
2) How has the air we breathe and the weather been affected up to now? locally? , regionally?, nationally?
3) How and to what extent has agricultural and park land been affected up to now ?
4) How will the quality and availability of water, air, and land, Earth’s life support systems, be affected in the near and more distant future ?

*IPCC is a group of more than 2000 of the world’s leading scientists, formed in 1988 to review the research on global warming and its potential impact.  The IPCC does not conduct its own scientific inquiries, but reviews worldwide research and issues regular assessment reports.

** The bio-region is typically determined biophysically by its watershed rather than politically.. Bio-regional  planning is done on the basis of maintaining and strengthening the watershed. It relies on local staples rather than their importation from distant areas . (Verhagen, 2004)


McGibben, B.  2012. Global warming’s terrifying new Math.  Rolling Stone, August
2nd, 2012 .

Verhagen, F. 2004. Contextual sustainability education: Towards an integrated     
educational framework for social and ecological peace. In  A.Wenden (ed.) Educating 
for a culture of social and ecological peace.
State University of New York Press,