Boris Lvin (bbb) wrote,
Boris Lvin
bbb

Еще образец "киотской" логики

Q. What percentage of the CO2 in the atmosphere has been produced by human beings through the burning of fossil fuels?

A. Over the last 150 years or so, the amount of CO2 released into the atmosphere due to human activity has exceeded the amount sequestered in biomass, the oceans, and other sinks. Let us assume that the more or less steady climb in CO2 concentration in the atmosphere from about 288 ppmv in 1850 (beginning of the "Industrial Revolution") to 367 ppmv in 1998 (http://cdiac.ornl.gov/pns/current_ghg.html) is fully attributable to activities by human beings (burning of fossil fuels, cement production, and land use changes). Then about 22% of the current atmospheric CO2 burden is due to the sum of these human activities [Please note that this approach implies there is no appreciable change in natural emissions of CO2 (e.g., volcanism) over that period].

To determine the percentage contribution from burning of fossil fuels alone requires further information and analysis. Given an atmospheric CO2 concentration of 367 ppmv as of 1998 (Keeling and Whorf 2000) (http://cdiac.ornl.gov/ftp/maunaloa- co2/maunaloa.co2) and a conversion factor of 1 ppmv CO2 = 2.13 GtC, about 780 GtC (780 billion tons of carbon) are estimated to reside in the earth's atmosphere as CO2 as of 1998.

Based on (1) data for carbon flux from land use changes for the period 1850 - 1990 (Houghton and Hackler 2001) (http://cdiac.ornl.gov/epubs/ndp/ndp050/ndp050.html), and (2) assuming a continuing flux rate of 2.1 GtC/yr from 1990 through 1998, we find that land-use changes during 1850 to 1998 resulted in a total net global carbon flux to the atmosphere of approximately 141 GtC. During this same period, data from Marland et al. (2001) (http://cdiac.ornl.gov/ndps/ndp030.html) indicate that about 263 GtC were released to the atmosphere from burning of fossil fuels (an additional 5 GtC were generated by cement production).

The estimated value of 288 ppmv CO2 in the atmosphere in 1850 is equivalent to 613 GtC. Thus total atmospheric carbon burden has increased by about 167 GtC since 1850 (i.e., 780 - 613 GtC), but total anthropogenic atmospheric input over the same period has been about 409 GtC (i.e., 141 + 268 GtC). It follows therefore that about 242 GtC, or 59%, of man's total input to the atmosphere, has been removed (sequestered) over that period. Approximately 64% of the net increase of 167 GtC [(263/409) x 167 = 107 GtC] is attributable to burning fossil fuel. That represents about 14% (107 / 780 GtC) of the estimated carbon (and therefore CO2) content of the atmosphere. As noted earlier, this estimate is based on the assumption that no appreciable change in natural emission rates of CO2 have occurred over that period.


http://cdiac.esd.ornl.gov/pns/faq.html

Выделение жирным шрифтом - мое. То есть авторы достаточно честны, чтобы четыре раза подчеркнуть - их расчеты базируются на совершенно нереалистичных допущениях. Но при этом они все равно предлагают свои расчеты, а читатели, очевидно, будут держать в голове и цитировать дальше именно расчеты, а не допущения. Более того, в этих расчетах они говорят о ВАЛОВЫХ (gross) антропогенных выбросах и фактически ЧИСТОЙ (net) динамике атмосферного содержания углекисловты. Если бы они дали оценки валовых природных выбросов и поглощений, то сразу стало бы ясно, насколько сильны их допущения и сомнительны выводы.
Tags: global warming
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