Direct Air Capture and Carbon Sequestration (DACCS) Continued

The figure below shows the results of a little experiment where a DACCS system is added to a global carbon cycle model to show what would happen if, starting in 2020, we began to remove carbon through DACCS to match the carbon emissions from burning fossils. The model begins in 1880 and runs up to 2014 using the actual human emissions of carbon, and then switches to a projection made by the IPCC for future carbon emissions.

The upper panel shows the gigatons of C from human emissions and the gigatons of C removed by DACCS, which begins in the year 2020. The lower panel shows how this change affects the global temperature change (green, in °C relative to the start), the atmospheric CO₂ concentration (red, in parts per million), and the ocean pH, which is inversely related to the acidity).

These results from a model of the global carbon cycle and the climate system shows what would happen if we used a DACCS system, starting in the year 2020 to counteract all of the carbon emissions from burning fossil fuels. The carbon removed by DACCS is shown in the upper panel along with the fossil fuel carbon emissions; it rises rapidly in the year 2020 and then tracks the carbon emissions, which effectively cancels out the carbon emissions. This results in a drop in atmospheric CO₂, a drop in temperature, and a rise in pH (higher pH values mean lower acidity).

Click for a text description of the DACCS figures with global carbon cycle model.

Top Graph: Human Emissions vs. DACS (Direct Air Carbon Capture and Storage).

Axes:
- X-axis: Labeled "Years," ranging from 1880 to 2100.
- Y-axis: Labeled "GT of Carbon," ranging from 0.00 to 30.00 GT (Gigatons).
Data Series:
- Human Emissions: Represented by a solid red line. This line shows a steady increase in human carbon emissions from 1880, with a significant rise post-1950, peaking around 2050, then slightly declining but still remaining high through to 2100.
- DACS: Represented by a blue dotted line starting around 2045, indicating the introduction of direct air capture and storage technology. This line shows a gradual increase in carbon removal via DACS, which helps to mitigate some of the human emissions but does not reduce them to zero by 2100.
Legend: Located on the right side, identifying:
- Red solid line: "human emissions"
- Blue dotted line: "DACS"

Bottom Graph: pCO2 Atm, pH, and Global Temperature Change

Title: Not explicitly provided but inferred from the context.
Axes:
- X-axis: Labeled "Years," ranging from 1880 to 2100.
- Y-axis: Three different scales for three variables:
  - Left Y-axis for pCO2 (partial pressure of CO2 in the atmosphere) in ppm (parts per million), ranging from 280.00 to 800.00 ppm.
  - Right Y-axis for pH, ranging from 7.80 to 8.20.
  - Right Y-axis for global temperature change in °C, ranging from -1.00 to 7.00°C.
- Data Series:
  - pCO2 Atm: Represented by a red line. This line shows an increase in atmospheric CO2 concentration from around 280 ppm in 1880, with a sharp rise post-1950, peaking around 2050, then slightly decreasing but still elevated by 2100.
  - pH: Represented by a blue line. This line shows a decrease in ocean pH (acidification) from around 8.20 in 1880, with a notable drop starting around 1950, continuing to decrease until around 2050, then leveling off but not recovering to pre-1950 levels by 2100.
  - Global Temp Change: Represented by a green line. This line shows the global temperature change, starting near 0°C in 1880, with a significant increase post-1950, peaking around 2050, then slightly decreasing but remaining high by 2100
- Legend: Located at the bottom, identifying:
  - Red line: "pCO2 atm"
  - Blue line: "pH"
  - Green line: "global temp change"

If we continue to burn fossil fuels as we have been (the scenario shown in the figure above), the cost of using DACCS to negate the emissions would be immense — a total of perhaps \$600 trillion by the end of the century. But if we also make drastic reductions in our carbon emissions, the cost of DACCS would be more manageable. This raises an important point — the cheapest thing to do is to switch to renewable energy (mainly wind and solar) and thus dramatically reduce our emissions. And, as we will see later, less money spent on geoengineering means more money to be spent on things like education, healthcare, and other things that improve our quality of life.