A climate change solution that's right under our feet
-
0:01 - 0:03So one of the most important solutions
-
0:03 - 0:07to the global challenge
posed by climate change -
0:07 - 0:10lies right under our foot every day.
-
0:10 - 0:12It's soil.
-
0:12 - 0:17Soil's just the thin veil
that covers the surface of land, -
0:17 - 0:21but it has the power to shape
our planet's destiny. -
0:22 - 0:26See, a six-foot or so of soil,
-
0:26 - 0:29loose soil material
that covers the earth's surface, -
0:29 - 0:34represents the difference between life
and lifelessness in the earth system, -
0:35 - 0:39and it can also help us
combat climate change -
0:39 - 0:42if we can only stop treating it like dirt.
-
0:43 - 0:44(Laughter)
-
0:44 - 0:46Climate change is happening,
-
0:46 - 0:49the earth's atmosphere is warming,
-
0:49 - 0:52because of the increasing amount
of greenhouse gases -
0:52 - 0:54we keep releasing into the atmosphere.
-
0:54 - 0:56You all know that.
-
0:56 - 0:59But what I assume you might not have heard
-
0:59 - 1:04is that one of the most important things
our human society could do -
1:04 - 1:06to address climate change
-
1:06 - 1:08lies right there in the soil.
-
1:10 - 1:14I'm a soil scientist who has been
studying soil since I was 18, -
1:14 - 1:18because I'm interested in unlocking
the secrets of soil -
1:18 - 1:23and helping people understand this
really important climate change solution. -
1:24 - 1:26So here are the facts about climate.
-
1:26 - 1:30The concentration of carbon dioxide
in the earth's atmosphere -
1:30 - 1:32has increased by 40 percent
-
1:32 - 1:35just in the last 150 years or so.
-
1:35 - 1:41Human actions are now releasing
9.4 billion metric tons of carbon -
1:41 - 1:43into the atmosphere,
-
1:43 - 1:46from activities
such as burning fossil fuels -
1:46 - 1:49and intensive agricultural practices,
-
1:49 - 1:52and other ways we change
the way we use land, -
1:52 - 1:54including deforestation.
-
1:55 - 2:01But the concentration of carbon dioxide
that stays in the atmosphere -
2:01 - 2:03is only increasing by about half of that,
-
2:04 - 2:08and that's because half of the carbon
we keep releasing into the atmosphere -
2:08 - 2:12is currently being taken up
by land and the seas -
2:12 - 2:15through a process we know
as carbon sequestration. -
2:16 - 2:20So in essence, whatever consequence
you think we're facing -
2:20 - 2:23from climate change right now,
-
2:23 - 2:28we're only experiencing the consequence
of 50 percent of our pollution, -
2:29 - 2:32because the natural ecosystems
are bailing us out. -
2:33 - 2:35But don't get too comfortable,
-
2:36 - 2:40because we have two major things
working against us right now. -
2:41 - 2:46One: unless we do something big,
-
2:46 - 2:48and then fast,
-
2:48 - 2:49emissions will continue to rise.
-
2:51 - 2:56And second: the ability
of these natural ecosystems -
2:56 - 2:59to take up carbon dioxide
from the atmosphere -
2:59 - 3:02and sequester it in the natural habitats
-
3:02 - 3:04is currently getting compromised,
-
3:04 - 3:09as they're experiencing serious
degradation because of human actions. -
3:10 - 3:12So it's not entirely clear
-
3:12 - 3:16that we will continue to get bailed out
by these natural ecosystems -
3:16 - 3:20if we continue on this
business-as-usual path that we've been. -
3:21 - 3:23Here's where the soil comes in:
-
3:23 - 3:28there is about three thousand billion
metric tons of carbon in the soil. -
3:28 - 3:32That's roughly about 315 times
the amount of carbon -
3:32 - 3:35that we release
into the atmosphere currently. -
3:35 - 3:39And there's twice more carbon in soil
than there is in vegetation and air. -
3:40 - 3:42Think about that for a second.
-
3:42 - 3:45There's more carbon in soil
-
3:45 - 3:48than there is in all
of the world's vegetation, -
3:48 - 3:54including the lush tropical rainforests
and the giant sequoias, -
3:54 - 3:56the expansive grasslands,
-
3:56 - 3:59all of the cultivated systems,
-
3:59 - 4:03and every kind of flora you can imagine
on the face of the earth, -
4:04 - 4:09plus all the carbon that's currently
up in the atmosphere, combined, -
4:09 - 4:10and then twice over.
-
4:12 - 4:17Hence, a very small change
in the amount of carbon stored in soil -
4:17 - 4:21can make a big difference
in maintenance of the earth's atmosphere. -
4:23 - 4:27But soil's not just simply
a storage box for carbon, though. -
4:27 - 4:30It operates more like a bank account,
-
4:30 - 4:33and the amount of carbon
that's in soil at any given time -
4:33 - 4:36is a function of the amount of carbon
coming in and out of the soil. -
4:38 - 4:41Carbon comes into the soil
through the process of photosynthesis, -
4:41 - 4:44when green plants take carbon dioxide
from the atmosphere -
4:44 - 4:47and use it to make their bodies,
-
4:47 - 4:50and upon death,
their bodies enter the soil. -
4:51 - 4:53And carbon leaves the soil
-
4:53 - 4:55and goes right back up into the atmosphere
-
4:55 - 4:58when the bodies of those
formerly living organisms -
4:58 - 5:01decay in soil by the activity of microbes.
-
5:02 - 5:06See, decomposition releases
carbon dioxide into the atmosphere, -
5:06 - 5:11as well as other greenhouse gases
such as methane and nitrous oxide, -
5:11 - 5:15but it also releases all the nutrients
we all need to survive. -
5:16 - 5:21One of the things that makes soil
such a fundamental component -
5:21 - 5:24of any climate change mitigation strategy
-
5:24 - 5:27is because it represents
a long-term storage of carbon. -
5:28 - 5:31Carbon that would have lasted
maybe a year or two -
5:31 - 5:35in decaying residue
if it was left on the surface -
5:35 - 5:40can stay in soil for hundreds of years,
even thousands and more. -
5:41 - 5:43Soil biogeochemists like me
-
5:43 - 5:48study exactly how the soil system
makes this possible, -
5:48 - 5:53by locking away the carbon
in physical association with minerals, -
5:53 - 5:56inside aggregates of soil minerals,
-
5:56 - 5:59and formation of strong chemical bonds
-
5:59 - 6:03that bind the carbon
to the surfaces of the minerals. -
6:04 - 6:07See when carbon is entrapped in soil,
-
6:07 - 6:10in these kinds of associations
with soil minerals, -
6:10 - 6:14even the wiliest of the microbes
can't easily degrade it. -
6:14 - 6:16And carbon that's not degrading fast
-
6:16 - 6:21is carbon that's not going back
into the atmosphere as greenhouse gases. -
6:22 - 6:24But the benefit of carbon sequestration
-
6:24 - 6:27is not just limited
to climate change mitigation. -
6:27 - 6:34Soil that stores large amounts of carbon
is healthy, fertile, soft. -
6:34 - 6:36It's malleable. It's workable.
-
6:37 - 6:39It makes it like a sponge.
-
6:39 - 6:42It can hold on to
a lot of water and nutrients. -
6:43 - 6:46Healthy and fertile soils like this
-
6:46 - 6:51support the most dynamic, abundant
and diverse habitat for living things -
6:51 - 6:54that we know of anywhere
on the earth system. -
6:55 - 7:02It makes life possible for everything
from the tiniest of the microbes, -
7:02 - 7:04such as bacteria and fungi,
-
7:04 - 7:06all the way to higher plants,
-
7:06 - 7:11and fulfills the food, feed
and fiber needs for all animals, -
7:11 - 7:13including you and I.
-
7:14 - 7:18So at this point, you would assume
that we should be treating soil -
7:18 - 7:20like the precious resource that it is.
-
7:20 - 7:22Unfortunately, that's not the case.
-
7:23 - 7:29Soils around the world are experiencing
unprecedented rates of degradation -
7:29 - 7:34through a variety of human actions
that include deforestation, -
7:34 - 7:37intensive agricultural production systems,
-
7:37 - 7:38overgrazing,
-
7:38 - 7:41excessive application
of agricultural chemicals, -
7:41 - 7:43erosion and similar things.
-
7:45 - 7:49Half of the world's soils
are currently considered degraded. -
7:50 - 7:54Soil degradation is bad for many reasons,
-
7:54 - 7:56but let me just tell you a couple.
-
7:57 - 8:03One: degraded soils have diminished
potential to support plant productivity. -
8:03 - 8:06And hence, by degrading soil,
-
8:06 - 8:12we're compromising our own abilities
to provide the food and other resources -
8:12 - 8:14that we need for us
-
8:14 - 8:18and every member of living things
on the face of the earth. -
8:19 - 8:21And second:
-
8:22 - 8:27soil use and degradation,
just in the last 200 years or so, -
8:27 - 8:32has released 12 times more carbon
into the atmosphere -
8:32 - 8:35compared to the rate at
which we're releasing carbon -
8:35 - 8:37into the atmosphere right now.
-
8:38 - 8:41I'm afraid there's even more bad news.
-
8:41 - 8:44This is a story of soils
at high latitudes. -
8:45 - 8:47Peatlands in polar environments
-
8:47 - 8:51store about a third
of the global soil carbon reserves. -
8:51 - 8:54These peatlands have
a permanently frozen ground underneath, -
8:54 - 8:56the permafrost,
-
8:56 - 9:01and the carbon was able to build up
in these soils over long periods of time -
9:01 - 9:06because even though plants are able
to photosynthesize during the short, -
9:06 - 9:08warm summer months,
-
9:08 - 9:12the environment quickly
turns cold and dark, -
9:12 - 9:16and then microbes are not able
to efficiently break down the residue. -
9:17 - 9:20So the soil carbon bank
in these polar environments -
9:20 - 9:23built up over hundreds
of thousands of years. -
9:24 - 9:28But right now, with atmospheric warming,
-
9:28 - 9:31the permafrost is thawing and draining.
-
9:32 - 9:35And when permafrost thaws and drains,
-
9:35 - 9:38it makes it possible
for microbes to come in -
9:38 - 9:41and rather quickly
decompose all this carbon, -
9:41 - 9:46with the potential to release hundreds
of billions of metric tons of carbon -
9:46 - 9:48into the atmosphere
in the form of greenhouse gases. -
9:49 - 9:53And this release of additional
greenhouse gases into the atmosphere -
9:53 - 9:56will only contribute to further warming
-
9:56 - 10:00that makes this predicament even worse,
-
10:00 - 10:05as it starts a self-reinforcing
positive feedback loop -
10:05 - 10:08that could go on and on and on,
-
10:08 - 10:10dramatically changing our climate future.
-
10:12 - 10:16Fortunately, I can also tell you
that there is a solution -
10:16 - 10:21for these two wicked problems
of soil degradation and climate change. -
10:21 - 10:23Just like we created these problems,
-
10:23 - 10:25we do know the solution,
-
10:25 - 10:28and the solution lies
in simultaneously working -
10:28 - 10:31to address these two things together,
-
10:32 - 10:36through what we call
climate-smart land management practices. -
10:36 - 10:38What do I mean here?
-
10:38 - 10:41I mean managing land
in a way that's smart -
10:41 - 10:44about maximizing
how much carbon we store in soil. -
10:46 - 10:47And we can accomplish this
-
10:47 - 10:52by putting in place
deep-rooted perennial plants, -
10:52 - 10:54putting back forests whenever possible,
-
10:54 - 10:59reducing tillage and other disturbances
from agricultural practices, -
10:59 - 11:03including optimizing the use
of agricultural chemicals and grazing -
11:03 - 11:07and even adding carbon to soil,
whenever possible, -
11:07 - 11:11from recycled resources
such as compost and even human waste. -
11:13 - 11:16This kind of land stewardship
is not a radical idea. -
11:17 - 11:21It's what made it possible
for fertile soils -
11:21 - 11:25to be able to support human civilizations
since time immemorial. -
11:26 - 11:28In fact, some are doing it just right now.
-
11:29 - 11:33There's a global effort underway
to accomplish exactly this goal. -
11:34 - 11:39This effort that started in France
is known as the "4 per 1000" effort, -
11:40 - 11:43and it sets an aspirational goal
-
11:43 - 11:50to increase the amount of carbon
stored in soil by 0.4 percent annually, -
11:51 - 11:55using the same kind of climate-smart
land management practices -
11:55 - 11:56I mentioned earlier.
-
11:57 - 11:59And if this effort's fully successful,
-
12:00 - 12:04it can offset a third
of the global emissions -
12:04 - 12:06of fossil-fuel-derived carbon
into the atmosphere. -
12:07 - 12:11But even if this effort
is not fully successful, -
12:11 - 12:15but we just start heading
in that direction, -
12:15 - 12:19we still end up with soils
that are healthier, more fertile, -
12:19 - 12:23are able to produce all the food
and resources that we need -
12:23 - 12:26for human populations and more,
-
12:26 - 12:28and also soils that are better capable
-
12:28 - 12:32of sequestering carbon dioxide
from the atmosphere -
12:32 - 12:34and helping with
climate change mitigation. -
12:35 - 12:39I'm pretty sure that's what politicians
call a win-win solution. -
12:40 - 12:42And we all can have a role to play here.
-
12:44 - 12:49We can start by treating the soil
with the respect that it deserves: -
12:49 - 12:54respect for its ability
as the basis of all life on earth, -
12:54 - 12:58respect for its ability to serve
as a carbon bank -
12:58 - 13:03and respect for its ability
to control our climate. -
13:04 - 13:05And if we do so,
-
13:05 - 13:08we can then simultaneously address
-
13:08 - 13:12two of the most pressing
global challenges of our time: -
13:12 - 13:15climate change and soil degradation.
-
13:15 - 13:21And in the process, we would be able
to provide food and nutritional security -
13:21 - 13:23to our growing human family.
-
13:23 - 13:25Thank you.
-
13:25 - 13:29(Applause)
- Title:
- A climate change solution that's right under our feet
- Speaker:
- Asmeret Asefaw Berhe
- Description:
-
There's two times more carbon in the earth's soil than in all of its vegetation and the atmosphere -- combined. Biogeochemist Asmeret Asefaw Berhe dives into the science of soil and shares how we could use its awesome carbon-trapping power to offset climate change. "[Soil] represents the difference between life and lifelessness in the earth system, and it can also help us combat climate change -- if we can only stop treating it like dirt," she says.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 13:42
Brian Greene edited English subtitles for A climate change solution that's right under our feet | ||
Brian Greene edited English subtitles for A climate change solution that's right under our feet | ||
Oliver Friedman approved English subtitles for A climate change solution that's right under our feet | ||
Oliver Friedman edited English subtitles for A climate change solution that's right under our feet | ||
Krystian Aparta accepted English subtitles for A climate change solution that's right under our feet | ||
Krystian Aparta edited English subtitles for A climate change solution that's right under our feet | ||
Krystian Aparta edited English subtitles for A climate change solution that's right under our feet | ||
Krystian Aparta edited English subtitles for A climate change solution that's right under our feet |