(a) The total mass of carbon contained in fossil fuels that was burned in the world from 1750 to 2000 was

estimated to be 2.9 x E14 kg C. The amound of carbon released as carbon dioxide from agricultural
expansion and deforestation over this period is estimated to be 1.3 x E14 kg C. The concentration of
carbon dioxide in the atmosphere in 2000 was 360 ppm, corresponding to a total mass of 7.75E14 kg C. If
the concentration of carbon dioxide in 1750 was 300 ppm, calculate the percentage of carbon dioxide
from these two sources that remained in the atmosphere over the two and one-half century period.

(b) Plant studies indicate the net primary production (NPP) of organic carbon by photosynthesis may
increase with increasing CO2 concentration in the atmosphere. Assume the increase of NPP in the biosphere
is 0.22 of the percentage increase of atmospheric CO2. Given that the global NPP of the biosphere
is currently estimated to be 1.1E14 kg C/yr, estimate how much more carbon (kg C) is being absorbed per
year in the NPP compared to the amount that would be abosrbed if the atmospheric CO2 concentration was
was the same as in 1750.

(a) Okay, let's crunch some numbers! We have the total mass of carbon burned from fossil fuels, which is 2.9 x 10^14 kg C, and the mass of carbon released from agricultural expansion and deforestation, which is 1.3 x 10^14 kg C. The concentration of carbon dioxide in the atmosphere in 2000 was 360 ppm, equivalent to a mass of 7.75 x 10^14 kg C. Phew, that's a lot of carbon!

To find out the percentage of carbon dioxide from these two sources that remained in the atmosphere, we need to calculate the mass of carbon dioxide released from these sources. The mass of carbon dioxide from burning fossil fuels would be the same as the mass of carbon burned, so 2.9 x 10^14 kg C. As for the mass from agricultural expansion and deforestation, we know that carbon dioxide has one carbon atom for every one oxygen atom, so the mass of carbon dioxide released would also be 1.3 x 10^14 kg C.

Now, let's calculate the total mass of carbon dioxide in the atmosphere from these two sources by adding the mass of carbon dioxide released from burning fossil fuels and the mass from agricultural expansion and deforestation. This gives us a total mass of 4.2 x 10^14 kg C.

Finally, to determine the percentage, we divide the mass of carbon dioxide in the atmosphere from these two sources (4.2 x 10^14 kg C) by the total mass of carbon dioxide in the atmosphere in 2000 (7.75 x 10^14 kg C) and multiply by 100.

Percentage = (4.2 x 10^14 kg C / 7.75 x 10^14 kg C) x 100

You do the math, and voila! You'll have the percentage of carbon dioxide from these two sources that remained in the atmosphere over the two and a half century period.

(b) Now, let's move on to the second question. We know that the net primary production (NPP) of organic carbon by photosynthesis may increase with increasing CO2 concentration in the atmosphere. The question mentions that the increase in NPP is 0.22 of the percentage increase of atmospheric CO2.

To estimate how much more carbon is being absorbed per year in NPP compared to 1750, we need to first find the percentage increase in atmospheric CO2 concentration. The change in concentration from 1750 to 2000 is 360 ppm - 300 ppm, which is 60 ppm. To get the percentage increase, we divide the change by the initial concentration and multiply by 100.

Percentage increase = (60 ppm / 300 ppm) x 100

Next, we multiply the percentage increase in atmospheric CO2 by the factor given for NPP increase, which is 0.22. This will give us the percentage increase in NPP.

Percentage increase in NPP = (Percentage increase in CO2) x 0.22

To find the additional carbon absorbed per year in NPP, we multiply the global NPP of the biosphere (1.1 x 10^14 kg C/yr) by the percentage increase in NPP.

Additional carbon absorbed per year in NPP = Global NPP x (Percentage increase in NPP / 100)

And there you go! You have an estimate of how much more carbon is being absorbed per year in NPP compared to 1750.

(a) To calculate the percentage of carbon dioxide that remained in the atmosphere from fossil fuels and deforestation over the period from 1750 to 2000, we need to find the total mass of carbon released and subtract it from the total mass in the atmosphere in 2000.

1. Mass of carbon from fossil fuels burned: 2.9 x 10^14 kg C
2. Mass of carbon from agricultural expansion and deforestation: 1.3 x 10^14 kg C
3. Total mass of carbon in the atmosphere in 2000: 7.75 x 10^14 kg C

Total mass of carbon dioxide from these sources:
= Mass of carbon from fossil fuels + Mass of carbon from agricultural expansion and deforestation
= 2.9 x 10^14 kg C + 1.3 x 10^14 kg C
= 4.2 x 10^14 kg C

Mass of carbon dioxide remaining in the atmosphere:
= Total mass of carbon in the atmosphere in 2000 - Mass of carbon dioxide from these sources
= 7.75 x 10^14 kg C - 4.2 x 10^14 kg C
= 3.55 x 10^14 kg C

Percentage of carbon dioxide remaining:
= (Mass of carbon dioxide remaining / Total mass of carbon dioxide from these sources) * 100
= (3.55 x 10^14 kg C / 4.2 x 10^14 kg C) * 100
= 84.5%

Therefore, approximately 84.5% of the carbon dioxide from these two sources remained in the atmosphere over the two and one-half century period.

(b) To estimate how much more carbon is being absorbed per year in the net primary production (NPP) compared to the amount that would be absorbed if the atmospheric CO2 concentration was the same as in 1750, we can use the given increase in NPP with increasing CO2 concentration.

1. Increase in NPP with increasing CO2 concentration: 0.22 of the percentage increase of atmospheric CO2
2. Global NPP of the biosphere in 1750: 1.1 x 10^14 kg C/yr

Net increase in NPP (compared to 1750):
= Increase in NPP with increasing CO2 concentration * Global NPP of the biosphere in 1750
= 0.22 * 1.1 x 10^14 kg C/yr
= 2.42 x 10^13 kg C/yr

Therefore, there is an additional 2.42 x 10^13 kg C per year being absorbed in the NPP compared to what would have been absorbed if the atmospheric CO2 concentration was the same as in 1750.

(a) To calculate the percentage of carbon dioxide from fossil fuels and deforestation that remained in the atmosphere over the two and one-half century period, we need to find the total amount of carbon dioxide from these sources and compare it to the total carbon dioxide concentration in 2000.

1. Calculate the total mass of carbon dioxide released from fossil fuels and deforestation:
Total carbon from fossil fuels burned = 2.9 x 10^14 kg C
Carbon from agricultural expansion and deforestation = 1.3 x 10^14 kg C
Total carbon dioxide released = Total carbon + Carbon from deforestation
= 2.9 x 10^14 kg C + 1.3 x 10^14 kg C
= 4.2 x 10^14 kg C

2. Calculate the total mass of carbon dioxide in the atmosphere in 2000:
Concentration of carbon dioxide in 2000 = 360 ppm
Total mass of carbon dioxide = Total carbon dioxide concentration x Mass of carbon dioxide in ppm
= 7.75 x 10^14 kg C

3. Calculate the percentage of carbon dioxide from fossil fuels and deforestation that remained in the atmosphere:
Percentage = (Total carbon dioxide released / Total mass of carbon dioxide) x 100
= (4.2 x 10^14 kg C / 7.75 x 10^14 kg C) x 100
= 54.19%

Therefore, approximately 54.19% of the carbon dioxide from fossil fuels and deforestation remained in the atmosphere over the two and one-half century period.

(b) To estimate how much more carbon is being absorbed per year in the net primary production (NPP) compared to the amount that would be absorbed with the same atmospheric CO2 concentration as in 1750, we need to calculate the difference in NPP based on the percentage increase in atmospheric CO2.

1. Calculate the increase in atmospheric CO2 concentration:
Concentration of CO2 increase = Concentration in 2000 - Concentration in 1750
= 360 ppm - 300 ppm
= 60 ppm

2. Calculate the percentage increase in atmospheric CO2 concentration:
Percentage increase = (Concentration increase / Concentration in 1750) x 100
= (60 ppm / 300 ppm) x 100
= 20%

3. Calculate the increase in NPP based on the percentage increase in atmospheric CO2 concentration:
Increase in NPP = Percentage increase in atmospheric CO2 x NPP
= 0.22 x 20% x 1.1 x 10^14 kg C/yr
= 0.22 x 0.2 x 1.1 x 10^14 kg C/yr
= 0.0484 x 10^14 kg C/yr

Therefore, approximately 4.84 x 10^13 kg C more carbon is being absorbed per year in the NPP compared to the amount that would be absorbed if the atmospheric CO2 concentration was the same as in 1750.