The CO2 Budget – Let’s talk numbers

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The recent Intergovernmental Panel on Climate Change (IPCC) issued its Annual Review - AR5 with a 

graphic that may help frame the Climate Change issue.

The notion of a CO2 Budget has always existed, but the published information is usually expressed in 

percentages, or a 2


C/450 ppm temperature/CO2 concentration combination that creates a scientific 

aura around the issue.

This aura allows cover for those who hide behind the “I am not a scientist” mantra. 

Since many of those in “hiding” usually profess great competency in planning and budgeting, one would 

think that the notion of a CO2 Budget would be in their “wheelhouse”.

The following table is extracted from BP’s Annual Statistical Review of Worldwide Energy – 2015, 

available as a downloadable Excel spreadsheet…..thank you BP. The full table provides a consistent basis 

for the annual CO2 Emissions by country back through 1965. I have extracted the most recent data for 

the U.S., China and India to help put this budget into perspective. 

The percentages are the 4-year compounded growth rate of the total.

The big take-away is that the world released 35.5Gt (35,498.7 Mt) of CO2 in 2014, increasing at almost 

1.88% per year, averaging the averages.


At this rate we will reach the 2900Gt budget in 2035 and on an 

increasing trajectory, headed toward 69Gt by 2050. 

The following graphic indicates a 58Gt, 6C trajectory, which we are currently exceeding, as well as 40Gt 

and 16Gt trajectories associated with 4


C and 2


C, respectively.

To reach the 16Gt level by 2050 requires a 2.19% per year reduction and, of course, would be on a 

declining trajectory. The U.S. component of this 16Gt target is shown as 1.3Gt.

The power generation 

component of this 1.3Gt U.S. total is 0.5Gt, or 500Mt, based on its historical 38% contribution.

It should also be noted that The U.S., China and India, the three biggest offenders are responsible for 

50% of the CO2 released. 

These numbers are useful in understanding and analyzing the various regulatory and administrative 

initiatives currently being discussed.

(Pete can be reached at