METEO 469 PROJECT #1
NAME: KAMILA DAGILOVA
DUE: 03.09.2015
Fossil Fuel Emission Scenario for Limiting Future Warming
1. Using the zero-dimensional EBM with the mid-range values of the gray body parameters
(and default settings for solar constant = 1370 W/m2 and albedo = 0.32) we estimate the
CO2 concentration for which we would achieve DIA of 2.5°C warming relative to preindustrial, which is 496.4 ppm (Figure 1.)
Figure 1
2. The 90% confidence range for climate sensitivity is 870 ppm (low end IPCC value) and
409 ppm (high end value) (Figure 2 and 3 respectively.) The 5% chance that the true
sensitivity is lower than the low end value, another 5% chance that the true sensitivity is
higher than the high end value gives us an interval of 429.45 to 826.5 ppm. The highest
value of CO2 concentration (high end value) we can reach and still keep the chance of
exceeding the DAI below 5% is 429.45 ppm (409 ppm + 409ppm*0.05).
Figure 2
Figure 3
3. Beginning with the default settings in the Kaya calculator, we are observing the projection
of the future CO2 emissions as a product of population, that is leveling out at 11 bln, GDP
(increase of 1.6%/year), Energy intensity (with the new efficient means of obtaining
energy there is a decrease of -1%/year) and CO2 efficiency (-0.3 change (decrease) of
the amount of carbon emitted per unit power, as we develop more less carbon-intensive
sources of energy.) The plot on the left in Figure 4 shows the blue curve which is a
projected future carbon emission given the business-as-usual assumptions values, and
the red dots show the historical values of carbon emission. The plot on the right of the
same figure shows in blue that we will approach 700 ppm of CO2 concentration (which
continues to rise) by 2100. Also there we can see various stabilization scenarios: red
curve shows the value of CO2 concentration if we were to stabilize the CO2
concentration at 350 ppm, the yellow curve – at 450, and so on. We can also look at the
carbon–free energy needed (Figure 5, left plot) or how much carbon-free energy we
would need to produce with the given assumptions to keep the CO2 concentration under
the specified levels (CO2 stabilization scenarios). Also we can see how our assumptions
relate to historical and projected GDP, energy intensity (projection follows the past few
decades) and carbon efficiency (illustrates the decreasing reliance on carbon-based
energy as time goes on) (Figures 6 and 7.)
Figure 5
Figure 6
Figure 7
To achieve an alternative emission scenario – stabilization to about 429.45 ppm CO2
concentration to avoid exceeding DAI of 2.5°C, we need to make some technology and future
policy changes and see how these changes will translate to the desired amount of carbon
emission. There are some limits to the changes:
1. We can control global population growth in accordance with the SRES scenarios, and it
should remain above current 6.8 bln.
2. The economic expansion rate can be changed in the range of the existing ± 1.2 (0.4 to
2.8%)
3. Energy intensity change should be in the interval of 0 to -2% (through new/improved)
4. Carbon intensity should be from 0 to -0.6%
Tuning these terms we can stabilize the CO2 concentration at the necessary threshold level of
429.45 ppm. Below (Figure 8), you can see that using the population = 8 bln, $GDP/person =
0.7%, Watts/$ = -2%, and Creleased/Watt = -0.6% we achieve the stabilization (right plot, dark
blue line) of carbon concentration = 429.92ppm by the year of 2100, but before that the
concentration reaches the peak of 433.3 ppm (in ≈2070). There are several various scenarios;
one of which represented by the red curve, leads to stabilization of 350 ppm, and doesn’t seem to
be realistic, because the atmospheric CO2 is currently at about 388ppm and increasing by about
2 ppm per year. According to that scenario we will have to reach the maximum of 395.4ppm in
2050 and than stabilize to 350 by the end of the century; however, if we continue to increase our
CO2 concentration at the same rate of 2 ppm per year, in 2050 the carbon concentration will be
equal to 458ppm. The scenario that will lead us to the desired stabilization ≈ 430 ppm (dark blue
curve) is possible if we follow those “optimistic” changes (i.e. population = 8 bln, $GDP/person =
0.7%, Watts/$ = -2%, and Creleased/Watt = -0.6%); comparing them to the default ones (i.e.
population 11 bln, GDP - increase of 1.6%/year, Energy intensity decrease of -1%/year and CO2
efficiency -0.3 % change), we will have to dramatically change governmental policies and our
behavior patterns to put us on the trajectories which will lead us to the desired output. Some
necessary governmental policies should be made to stabilize the population growth at
significantly low level; new technology should be developed and existing technology should be
improved to bring the energy efficiency to -2%; policies favoring the non-carbon based energy
sources should be made, etc. The other scenarios (yellow, green, purple, light-blue curves) show
slightly easier stabilization ways, but they all stabilize to values greater than our expected
threshold.
Figure 8
4. According to figure 9 (left plot), the population reaches 7.78 bln by the end of the century
following the trajectory of the A1 and B1 scenario families (IPCC Special Report on
Emission Scenarios, Lutz, 1996), which combines low fertility with low mortality and
central migration rate assumptions. If low population growth and decline in ferility in
today's industrialized countries continues, with stabilization of growth in Asia, in addition
to new policies, it would be possible to stabilize the population at this significantly low
level. Nowadays, about half of the developing countries have national population policies
– it’s necessary to increase the number of countries, which will have strict policies, family
planning programs, effective contraceptive options access, etc. to decrease the 1.5%
population growth rate. If we look at the plot to the right (Figure 9), we see that the slope
of the predicted scenario is more gradual comparing to the slope of the historical values
of the economic expansions. There are some uncertainties in future gross world product
levels related to the rate of the population growth and the future productivity growth
(especially in developing countries) (usually, there is a relationship: high population
growth means lower per capita income growth, whereas low population growth means
higher per capita income growth). This term will be difficult to bring down to 0.7% from
the default 1.6%.
Figure 9
Figure 10
Energy intensity plot (figure 10) shows the significantly decreasing amount of watts/dollar
by 2100 at a higher rate of decrease comparing to past historical rate. The technological
changes are also considered to be dynamic with future improvement rates subject to
considerable uncertainty. Bringing the energy efficiency to -2% means we should follow
the scenario of A1B of technology improvements in table 1:
Table 1
This scenario assumes significant innovations in energy technologies, which improve
energy efficiency and reduce the cost of energy supply through the use of solar, wind,
and other modern renewable energies, and significant progress in gas exploration,
production, and transport. Figure 11 (left plot) shows the decreased amount of carbon
emitted per unit of energy production by the end of the century: as we find new ways to
extract and sequester Co2 and switch to renewable energy sources and non-fossil fuel
sources we certainly expect a decline in this term. So we should follow A1 and B1
scenario groups that map the structural transitions toward higher shares of non-fossil
energy in the future.
Figure 11