This page gives references to climate projections done by the Intergouvernmeltal Panel on Climate Change (IPCC). Of special interest is the models used for the thermal response to increasing levels of atmospheric content of carbon dioxide. The projections done by IPCC will be used together with measured and reported data on temperature increase and CO2 contents to extract the basic response function to a stepwise increase of carbon dioxide in the atmosphere.
Figure 1 shows the projected temperature increase as a response to a doubling of the CO2 contents within the next 70 years, stable thereafter.
Figure 1.Projected temperature increase after 70 years
of 1% annual increases of CO2 in the atmosphere. This gives a doubled CO2 content
after 70 years. Note that the temperature levels off very fast after a stabilization
of the CO2-level. The time to 50% of the remaining temperature increase is according
to this graph around 40 years.
Source: http://www.grida.no/climate/ipcc_tar/wg1/345.htm#fig91
According to this graph IPCC assumes around 3,5 degrees C increase after a doubling of the CO2 contents from today's 380 to 760 ppm. Before that we have had close to one degree C increase after 100 ppm increase from 280 to 380 ppm. Thus, IPCC assumes that in total an increase of 480 ppm will result in a temperatuyre increase of 4,5 degrees C or around 1 degree C per 100 ppm CO2.
Figure 2 shows the thermal response to a peak (not a step function, though) according to the same organisation: Although the increase in CO2 is not a step function but a ramp the time to 50% of temperature increase looks to be around 50 years, quite in line with the projections made in Figure 1..
Figure 2. Calculated thermal response to a somewhat slower
reduction of annual CO2 outlet than assumed in Figure 1.
Source: http://www.grida.no/climate/ipcc_tar/vol4/english/fig5-2.htm
It is clear that IPCC here assumes a very fast response to increasing levels of carbon dioxide in the atmosphere. The temperature starts immediately to level off once the increasing levels of CO2 also slows down.
However, in Figure 3 a quite different picture is given from another IPCC report. Here the thermal response is assumed to need 120-150 years to reach half of the final temperature level after a step response.
Figure 3. Time to 50% increase of different climate characteristics
after a stepwise increase in atmospheric CO2 contents. For the temperature this
responsetime is estimated to be 120-150 years, quite in contrast to the assumptions
used for Figures 1 and 2.
Source: http://carto.eu.org/article2515.html
Figure 4 shows the connection between temperature and CO2 contents over the last 420 000 uears. Here we can see that 10 degrees C always correspond to 100 ppm increase in CO2 level. This is far away from the one degree C that IPCC expects to be the response to an increase of 100 ppm CO2.
Figure 4. The variation in atmospheric contents of CO2
and temperature since 420 000 years back.
Source: http://carto.eu.org/article2481.html
The data in Figures 1 and 2 can be used to extract the thermal response function to a stepwise increase in atmospheric contents of carbon dioxide. Likewise it is also possible to analyse already reported temperature/CO2 data to see what history already has taught us about the thermal response. Figure 5 shows more recent data since 1850 on CO2 and temperature anomalies.
Figure 5. Reported increase of CO2 and temperature since 1850
An analysis of the IPCC data and the data presented in Figure 5 gives the response patterns shown in Figure 6. The best fit between calculated and reported data was obtained when the final thermal response to an increase of 100 ppm was 5,45 degrees C. According to IPCC (Figures 1 and 2) the time to 50% of final temperature is 37 years while our model says 113 years, quite in line with Figure 3. A sensitivity analysis of our model using minimum and maximum temperature lines from Figure 5 gave a response time varying from 97 years (max temp line), 113 years (mean temp line, as in Figure 5) and 127 years for a low temperature line. Thus, there is no doubt that reported data actually supports the estimate made by IPCC in Figure 3 but certainly not in Fiures 1 and 2.
Figure 6. The response pattern according to IPCC projections and according to historical data.
Figure 7 gives the projected temperature increase from a doubling of CO2 contents to 2075 and stable thereafter.
Figure 7. The calculated thermal response to an increase by 400 ppm of CO2 contents by 2075 according to the two models.
Note that the red line in Figure 7 (IPCC) is similar to Figure 1 that levels off at 3,5 degrees while Figure 7 (4,3) includes the 0,8 degrees temperature increase since 1800 up till now. According to Figure 4 a temperature increase of 10 degrees C has always been followed by an increased level of atmospheric CO2 of 100 ppms. Now, when we add another 400 ppms IPCC believe that this will cause the temperature to increase by only 4,3 degrees or 1,1 degrees per 100 ppms. In our analysis the best fit to reported data was obtained when the final temperature increase for 100 ppms was 5,45 degrees C.
| Source |
Temp increase related to 100 ppm
|
| Historic data, 420 000 y |
10
|
| Our model |
5,45
|
| IPCC model |
1,1
|
Table I. Temperature increase related to 100 ppm increase of atmospheric contents of CO2.
If we manage to completely stop the increasing level of CO2 by year 2010 then the projected temperature would look as shown in Figure 8 during the next coming decades according to the two models. The graph also shows that our model fits much better to already reported data than the IPCC model does. According to our model the final temperature increase will still be around 6 degrees C, even if we manage to stop further increases in CO2 by year 2010.
Figure 8. Temperature increase according to two models if the CO2 content could be stabilized already from year 2010.
Note that the IPCC model, as extracted from Figure 1, predicts only 0.6 degrees C of increase from 2010 up to 2100. 50% of that, e.i. 0.3 degrees C is expected to happen within the first 20-30 years. In the latest IPCC report there is a graph showing what temperature increase that is expected if the GHG was held constant from year 2000. Also here the increase is plotted as 0.6 degrees up to year 2100. See Figure 9. Also here the time to 50% increase is 20-30 years. This shows that the method is applicable, but it also shows that the IPCC model does not correctly depict what really has happened since 1950. This seems to be wishful science!
Figure 9. The temperature increase for different scenarios. Source: http://www.ipcc.ch/SPM2feb07.pdf
The authorities need to assure that the most correct model is being used as a base for climate policy and corrective actions to apply. The official picture looks too optimistic and may have been influenced by strong economic interests from the car and oil industry. The fast increase in atmospheric CO2 contents since 1970 up till now has not yet had the time to manifest itself in corresponding temperature increases. There is more to come - like it or not!
The authorities also think that if large companies and organisations apply carbon trading, the problem will be solved. Nothing could be more wrong. If all customers have unlimited carbon release rights (millionaires in CO2 if you wish) why should the companies try to limit the GHG pollution from their products? The customers would not care, anyway!
It is only if we all have a limited amount of CO2 to release every month that we will see the beginning of a competitive carbon trading market. The company providing the best CO2-specification will win the market. And a real change will happen very fast. We know since WW2 that ration cards worked well for sugar and coffee, so why not for CO2? Especially since we today can manage ration cards just as easy as any other credit card.