This document discusses the need to rebuild soils and ecosystems to help mitigate climate change. It notes that 2300 gigatons of carbon is stored in soils. Strategies proposed include rapidly reducing fossil fuel use and avoiding releasing carbon from soils, as well as accelerating carbon uptake through restoring forests, grasslands, wetlands and soils. Aggressive sequestration through these natural solutions could boost net removals from the atmosphere and help balance carbon dioxide levels sooner. The document emphasizes that a restored global biosphere is needed to accelerate removing carbon dioxide from the atmosphere, as oceans alone cannot do this, and restoring natural ecosystems is an essential imperative.

1. Additional reasons for rebuilding
soils and ecosystems
William Moomaw
Biodiversity for a Living Climate
Tufts University
November 26, 2014

3. The allocation of carbon (C) in the
biosphere
• 800 GT of carbon is in the atmosphere as CO2
• Carbon in deep oceans is 37,000 GT and
carbon in surface ocean is 1000 GT mostly as
carbonate
• 2300 GT of C is found in soil
• 500 GT is found in living organisms mostly in
forest trees

4. The amount of CO2 in the atmosphere depends
upon rate of addition minus rate of removal
• Each year about 9 GT is released to the
atmosphere by human activity from burning
fossil fuels and deforestation and soil
degradation
• About 3 GT of this is absorbed by the
terrestrial biosphere
• About 2 GT is absorbed by the oceans
• Net 4 GT is added to the atmosphere each
year

5. Comparisons of sinks
• Burning all fossil fuels would add 12.5 x the
current amount of CO2 to the atmosphere
• Burning all forests and plants would add
0.63 x current amount
• Adding all soil carbon would add 2.9 x current
amount

6. The goal
• The ultimate objective of this Convention … is to
achieve … stabilization of greenhouse gas
concentrations in the atmosphere at a level that
would prevent dangerous anthropogenic
interference with the climate system.
• Such a level should be achieved within a time-frame
sufficient to allow ecosystems to adapt
naturally to climate change, to ensure that food
production is not threatened and to enable
economic development to proceed in a
sustainable manner.

7. Strategies
• Reduce the 9 GT of carbonfrom human
activity
– Rapidly reduce use of fossil fuels
– Avoid releasing carbon dioxide (and methane)
from soils and plants
• Accelerate the uptake of carbon dioxide in
soils and plants by restoring forests,
grasslands, wetlands and soils

8. Think of CO2 in the Atmosphere as a Bathtub
Emissions
CO2 in the atmosphere
Net Removals
The tub is filled by
emissions and drained by
net removals into oceans
and biomass.
The inflow is roughly
double the outflow
As long as emissions per year exceed removals, the
level of water (CO2) in the bathtub continues to
rise.

9. Reducing Emissions Post 2050 Puts Us On
Track to Levelize CO2 around 550 ppm
Fossil Fuel Emissions
The “flat path”
plus post 2054
reductions
Emissions exceed net removals all the way to 2100!
24 B
18 B
12 B
6 B
0
2000 2020 2040 2060 2080 2100
TonC/year
CO2 in the Atmosphere
800
700
600
500
400
300
2000 2020 2040 2060 2080 2100
ppm
The outcome of the
“flat path” plus post
2050 reductions
Goal

10. What Happened? Why Didn’t
Emissions Level?
Total Emissions and Removals
24 B
18 B
12 B
6 B
0
2000 2020 2040 2060 2080 2100
TonC/year
Despite reductions, Emissions exceeded
Net Removals through 2100.
CO2 in the atmosphere will rise until
the two meet.
CO2 in the Atmosphere
800
675
550
425
300
Goal
2000 2020 2040 2060 2080 2100
Emissions
Net Removals

11. It Will Take an 80% Reduction in Fossil
Fuel Emissions
Fossil Fuel Emissions
At this point, emissions equal net removals by 2050!
24 B
18 B
12 B
6 B
0
2000 2020 2040 2060 2080 2100
TonC/year
CO2 in the Atmosphere
800
700
600
500
400
300
2000 2020 2040 2060 2080 2100
ppm
Goal

12. • Approximately one-third of 230 GT carbon
dioxide added to the atmosphere is from soils
• Need to shift to restorative development,
mobilize the biosphere and accelerate carbon
storage in plants and soils
• NOTE! Carbon removal from the atmosphere
to the soils happened slowly, but can be
released rapidly
• Can we accelerate the uptake?

13. Aggressive Sequestration can boost
removals
Sources of Total Removals
6 B
4.475 B
2.95 B
1.425 B
-100 M
oceans
1900 1930 1960 1990 2020 2050 2080
Time (year)
TonC/year
Biomass + soils
seq.
CO2 in the Atmosphere
800
700
600
500
400
300
Goal
2000 2020 2040 2060 2080 2100
ppm
Results with 80% reduction in fossil fuel emissions plus 1.6
GTC/year in additional sequestration by 2050

14. The Added Sequestration Boosts Net
Removals
Total Emissions and Removals
24 B
18 B
12 B
6 B
0
2000 2020 2040 2060 2080 2100
TonC/year
Net Removals without
additional
sequestration
Net Removals with
additional
sequestration
So CO2 in the atmosphere
balances out a little earlier and
lower

15. Another problem
• “This paper shows that the climate change that
takes place due to increases in carbon dioxide
concentration is largely irreversible for 1,000
years after emissions stop.”
• Following cessation of emissions, removal of
atmospheric carbon dioxide decreases radiative
forcing, but is largely compensated by slower
loss of heat to the ocean, so that atmospheric
temperatures do not drop significantly for at
least 1,000 years.
• S. Soloman et al, PNAS, 2009)

16. Note that CO2 persists for more
than a millennium after emissions
cease at the peak, and
temperatures remain high.

17. Only a restored global biosphere can
accelerate the removal of carbon
dioxide from the atmosphere
• We cannot accelerate the uptake of carbon
dioxide from the atmosphere by the oceans
• We can only increase the rate of uptake by
plants and soils
• To avoid irreversible climate change
restorative development to rebuild forests,
grasslands and wetlands and their soils is not
an option
• It is an essential imperative!

18. Let us begin NOW!