Using simulators to determine the amount of carbon free energy needed to keep carbon dioxide levels in the atmosphere below 500 parts per million.

1. How Much Carbon Free Energy
is Needed in Coming Years?

2. Supporting Data
● The Emissions Gap
Report 2013.
● United Nations
Environment Program
(UNEP), November
2013
● Includes projections
of world carbon
emissions up to 2050
under various
scenarios.

3. Current Emissions
● “The most recent estimates of global
greenhouse gas emissions are for 2010 and
amount to 50.1 gigatonnes of carbon dioxide
equivalent (GtCO2e) per year (range: 45.6–54.6
GtCO2e per year).” UNEP 2013 at page xi
● This estimate can be converted to GtC by the
factor 3.67.
● The 50 GtCO2 estimate is equivalent to 13.6
GtC

4. What is the emission level for 2015?
● UNEP 2013 does not give historical data past
2010. However, assuming business as usual,
the projected emissions for 2020 are 59
GtCO2e/yr or 16 GtC/yr.
● Considering the failure of governments to
address the problem since 2010, it seems likely
that the emission level for 2015 must be about
54.5 GtCO2e/yr or 14.85 GtC/yr.

5. What should be the target emission
for 2020, assuming drastic action?
● “Based on a limited number of new studies,
least-cost emission pathways consistent with
the 1.5° C target have emission levels in 2020
of 37–44 GtCO2e per year, declining rapidly
thereafter.” Id. page xii
● The report assumes 44 GtCO2e/yr in 2020 as a
basis for targets set for 2025, 2030 and 2050.
This is equivalent to 12 GtC/yr.

6. What are the emission targets for
2025, 2030, and 2050?
● “In the scenarios assessed in this report, global
emission levels in 2025 and 2030 consistent
with the 2° C target amount to approximately 40
GtCO2 e (range: 35–45 GtCO2e) and 35
GtCO2e (range: 32–42 GtCO2e), respectively.
In these scenarios, global emissions in 2050
amount to 22 GtCO2e (range: 18–25 GtCO2e).
These levels are all based on the assumption
that the 2020 least-cost level of 44 GtCO2e per
year will be achieved.” id at xiii
● 40 GtCO2 is 10.9 GtC/yr, 22 GtCO2 is 6 GtC/yr

7. According to UNEP 2013, what
research supports these
projections?

8. What interactive climate simulations
tools are available to analyze the
implications of these projections?
ISAM integrated
impacts of climate
change simulation.
http://climatemodels.u
chicago.edu/isam/
KAYA Identity
Scenario
Prognosticator
http://climatemodels.u
chicago.edu/kaya/

9. What can be learned from
the ISAM simulator?
● This model was
developed at a time
when it was assumed
that the world could
act in a timely
manner.
● To be useful, the
default values of the
simulator must be up
dated based on
UNEP 2013.
● In order to stabilize
emissions by 2100, I
have updated the
model default values
as follows:

11. Using the KAYA tool
to determine feasibility
● The KAYA tool requires an estimate of world
population assuming that zero population
growth can be reached by 2100.
● According to my source (News, National
Geographic): “There's an 80 percent chance,
the authors conclude, that the actual number of
people in 2100 will be somewhere between 9.6
and 12.3 billion.”
http://news.nationalgeographic.com/news/2014/
09/140918-population-global-united-nations-
2100-boom-africa/

12. The KAYA tools allows other
parameters to be set based on
historical trends.
● Other parameters include GDP per person in
dollars, which is a measure of increasing
prosperity and demand for products in the
world.
● Also, there is a parameter for energy
consumption in Watts per year per GDP dollar.
● And, a parameter for energy efficiency in Tons
of Carbon per Watt of energy.

13. KAYA prediction of carbon free
energy needed to reach goals
● The following parameters were set based on
the population estimate for 2100 of 12 billion
people on the planet.

15. Conclusions
● The KAYA modeler was too conservative, as
can be seen from the fact that the historical fit
placed 2015 emissions at 9.5 GtC/yr, while we
suspect that the actual number for 2015 is
nearly 15 GtC/yr.
● Even with the conservative estimate, the model
shows we will need at least 50 TeraWatts of
Carbon Free Energy by 2100, beginning with
over 10 TeraWatts by year 2020 if we mean to
keep CO2 below 500 ppm by 2100.