Role of agriculture in climate change and vice versa

1. Agriculture and Climate Change
Bijay-Singh
Punjab Agricultural University, Ludhiana 141 004
bijaysingh20@hotmail.com

2. What is climate?
Climate is an average of weather
(temperature, rainfall...) over a “long”
time (more than 2-3 weeks).

3. Climate Change and Environmental Change
Dictionary.com
Climate change : A long-term change in the earth’s
climate, especially a change due to an increase in the
average atmospheric temperature:
Environmental Change: A change in precipitation
or global temperatures. Environmental change may be
the result of natural occurrences or impacted by
human activity.

4. What makes climate change?
 Changes in the sun
 Changes in the earth's orbit
 Changes in the clouds
 Changes in ice sheets
 Volcanic eruptions
 Changes in the gases in the atmosphere (Greenhouse effect)
 Internal Wiggles (for example El Nino)
Some cause bigger changes, some cause small changes
Some cause slower changes, some cause fast changes
Some cause changes that last, some cause changes that go away fast
 Climate changes can be natural or human caused.
 Humans can affect the climate by changing the gases
in the atmosphere (greenhouse effect)

5. 5
1. The Natural Greenhouse Effect
2. The Enhanced Greenhouse Effect
The first being useful, the second, well who knows?
There are two sources of
the Greenhouse Effect

6. 6
The Natural Greenhouse Effect
• Without it, Earth would have no living
things and would be more like Venus or
Mars
• This is because the temperature would
be on average 300C colder than it is

7. The Natural Greenhouse Effect at work
• The Earth is covered by a blanket of gas.
• The energy from the Sun reaches the
Earth’s surface, where some of it is
converted to heat energy.
• Most of the heat( blue arrows) is re-
radiated towards space, but some is
trapped by the greenhouse gases in the
atmosphere.
• This natural effect allows the Earth’s
temperature to be kept at a level
necessary to support life.

8. But then there is the Enhanced Greenhouse
Effect
• Look how this is different!
• Much more of the heat from
the sun gets trapped in the
atmosphere
• So the Earth gets hotter

9. ● Carbon dioxide (CO2) is a major greenhouse gas
● Human burning of fossil fuels, and plants releases CO2
Human influence on climate:
the Greenhouse Effect

10. The most important human-affected greenhouse gases are:
Greenhouse Gas
Life Span in the
Atmosphere
Heat-Trapping
Effectiveness
(1 is lowest)
Carbon Dioxide (CO2) 2-30 years 1
Methane (CH4) 6-11 years 20-30 (21)
Nitrous Oxide (N2O) 120-150 years 296
Fluorinated Gases 65-111 years 15,000-20,000

11. Have we changed the climate?
Changes in global temperature over the last 125 years

12. Have we changed the climate?
Changes in global temperature over the last 1,000 years

13. * From: IPCC, 2007: Summary for Poicymakers. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth
Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor
and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Have we changed the climate?

14. 1928
2000
The South Cascade
glacier retreated
dramatically in the 20th
century
Have we changed the climate?
Glaciers are retreating
all over world

15. Climate change: Vulnerability to sea level rise

16. Sea level rise in the Indian subcontinent
Bangladesh
• Displace 13 million
• 16% of national
rice production lost
India
• Displace 7 million,
est. cost $Bn 230
• Inundate 1700 km2 agricultural land
• Necessitate 4000 km of dykes and sea walls
• Submerge 576 km2 total land and 4200 km of roads

17. Bangladesh is projected to lose about 17% of its land
area with a sea level rise of one meter - very difficult to
adapt due to lack of adaptive capacity
projected
present

18. Summary of Projected Climate Changes
• Temperature to increase 3oC by 2050 and 5oC by 2070 over
land areas
• Precipitation increases in high latitudes (temperate) but a
drying in mid-latitudes (sub-tropics) over Asia
• Equatorial tropical zone – uncertain but little mean change
expected
• No increase in cyclone frequency but intensity could
increase by 10-20%
• Accelerated melting of glaciers – 65% of China’s glaciers
will not exist by 2050 with current and projected warming
trends
• Sea level rise

19. WFP (World Food Programme) is the world’s largest humanitarian agency fighting hunger

20. Agriculture and Climate Change:
A three-fold relationship
I. Agriculture as a contributor to Climate Change
II. Impacts of Climate Change on Agriculture
III. Agriculture as a potential moderator of Climate
Change

21. I. Agriculture as a contributor to Climate Change
Source of 30% of total global anthropogenic emissions of
GHGs
• Particulate matter and GHGs from land
clearance by fire and burning of residues
• > ½ total global anthropogenic emissions
of CH4 and N2O
– CH4: from rice and livestock
production
– N2O from fertilizers and manure
(FAO 2003, Gomiero et al. 2008)

22. Agriculture’s contribution to GHGs
Carbon
dioxide
Methane Nitrous
oxide
Land use
change,
especially
deforestation
Ruminants Livestock
(including
manure
applied to
farmland)
Rice
production
Mineral
fertilizers
Biomass
burning
Biomass
burning

23. Nitrogen fertilizers and N2O production in
agricultural soils
• Generally there is large emission of N2O
immediately after application of fertilizer N
• After about 6 weeks, the emission rate falls
and fluctuates around a low level
• On an average , emission of N2O from
different fertilizer types: can be calculated as:
N2O emitted = 1.25 % of kg N applied

24. Atmospheric concentrations of nitrous oxide over the last 10,000 years (large panels) and since
1750 (inset panels). Measurements are shown from ice cores (symbols with different colours for
different studies) and atmospheric samples (red lines). The corresponding radiative forcings are
shown on the right hand axes of the large panels. (Source IPCC, 2007)

25. N2O emissions from various source categories in
India in Gg-N2O (Source: Garg et al. 2006)
Source categories 1985 1990 1995 2000 2005 Compounded
annual growth
rate (%)
Synthetic fertilizer use 80 94 109 129 151 3.2
Field burning of
agricultural residues
15 18 21 21 20 1.4
Indirect soil emissions 17 19 21 25 30 2.9
Manure management 4 5 6 6 8 3.9
Fossil fuel combustion 7 9 12 15 19 4.9
Industrial processes 6 7 9 12 16 5.0
Wastes 5 6 7 8 9 2.8
Total N2O 134 158 185 217 253 3.2

26. N2O emissions in India in the reference scenarios 2000 and
2020 (Source: Garg et al. 2004)

27. II. Impacts of Climate Change on Agriculture
Four main climate related drivers on agriculture:
1. Elevated carbon dioxide
2. Rainfall and associated water resource availability
3. Temperature – both direct and indirect through
evaporation
4. Extreme weather events (wind, flood damage)
These interact to affect agricultural productivity, quality,
pests and diseases.
• Sea level rise and surge – inundating and ruining coastal
agricultural lands

30. Vulnerability of Asian Sectors Related to Agriculture to Climate
Change
Regions Food and Fibre Water
Resources
Coastal
Ecosystems
Arid and semi-arid Asia
Central Asia Highly vulnerable Highly
vulnerable
Moderately
vulnerable
Tibetan Plateau Slightly or not
vulnerable
Moderately
vulnerable
Not applicable
Temperate Asia Highly vulnerable Highly
vulnerable
Highly vulnerable
Tropical Asia and Small Island States
South Asia Highly vulnerable Highly
vulnerable
Highly vulnerable
Southeast Asia Highly vulnerable Highly
vulnerable
Highly vulnerable

31. III. Agriculture as part of the solution?
 Increasing carbon sequestration through land
management
 Agroforestry
 Rotations with cover crops, green manure
 Conservation tillage
 Could reduce global CO2 emissions by 5-15%
 Organic farming (but limited benefits)
 Enhances carbon storage in soil
 Biogas digesters?
(Gomiero et al. 2008, FAO 2003, Niles et al. 2002)

32. Soil is a part of the solution
for climate change
• Soil plays a pivotal role in global carbon and nitrogen
cycles.
• The amount of carbon stored in soil organic matter is
nearly three times higher than that in the above ground
biomass and around two times as high as in the
atmosphere
• Thus even small changes in soil organic carbon content
can have great impact on CO2 concentrations in the
atmosphere.

33. • It is estimated that soils can sequester around
20 Pg (Peta gram, 1015 g) C in 25 years, more
than 10 % of the anthropogenic emissions.
• The maintenance of existing carbon reservoirs
is among the highest priorities in striving for
climate change mitigation.
Soil is a part of the solution
for climate change

34. • Global mitigation potential from agriculture (excluding fossil
fuel offsets from biomass) by 2030 is estimated to be 5.5-6.0 Gt
CO2-eq/yr (G or giga is 109)
• Soil carbon sequestration has an estimated 89% contribution to
the technical potential
• 70% of the mitigation potential is in developing countries
• GHG emissions could also be reduced by substituting fossil fuels
with energy produced from agricultural feed stocks (e.g., crop
residues, dung, energy crops)
• Agricultural GHG mitigation options are cost competitive with
non-agricultural options (e.g., energy, transportation, forestry)
• Energy efficiency in agri-production (e.g., improved agronomic
practices, nutrient use, tillage, and residue management)
Agriculture offers multiple solutions to
climate change mitigation

35. Remember!
Climate change mitigation
will never be the main goal
for agriculture.

36. Climate-smart agriculture
Agriculture that sustainably
• increases productivity
• increases resilience (adaptation)
• reduces/removes GHGs and
• enhances achievement of national food
security and development goals

37. Two main goals of our times
1. Achieving food security
2. Avoiding dangerous climate change
We must reach both!

38. Thanks!