Climate change and agriculture: Adaptation and mitigation stategies

Abstract

Changes in climate can be expected to have significant impacts on crop yields through changes in temperature and water availability. The purpose of mitigation and adaptation measures is therefore to attempt a gradual reversal of the effects caused by climate change and sustain development. There are several mitigation and adaptation practices that can be effectively put to use to overcome the effects of climate change with desirable results. These methods fall into the broad categories of under crop/cropping system-based technologies, resource conservation-based technologies and socio-economic and policy interventions. These measures are discussed to suggest effective strategies among them to combat climate change with specific reference to India.

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Indian Journal of Agronomy 54(2): 226__230 (June 2009)
Climate change is a complex alteration of climate,
subtle and continuous, yet extremely important through its
consequences on vegetation of various types that thrived
under constant or relatively unchanged climates. The ef-
fects of climate change have reached such an extent that
irreversible changes in the functioning of the planet are
feared. Some of the main effects of climate change with
specific reference to agriculture and food production espe-
cially during the last decade are: increased occurrence of
storms and floods; increased incidence and severity of
droughts and forest fires; steady spreading out of frost-free
intervals and potential growing season; increased fre-
quency of diseases and insect pest attacks; and vanishing
habitats of plants and animals.
Apparently, these modifications of previously stable
climates imply an obvious warming trend and a growing
climatic variability impacting the exiting ecosystem. It is
important for the international scientific community to use
all accessible knowledge to stop or reverse this trend to the
maximum extent possible. There have been various at-
tempts and viable measures in the past to bring down at-
mospheric greenhouse gases (GHGs) to slow down cli-
mate change (Boer et al., 2000). However, if the warming
trend continues at its current pace, these may soon prove
inadequate. The early impacts of climate change already
are being felt worldwide. Future impacts will affect a
broad array of human and natural systems, with conse-
quences for human health, food and fiber production, wa-
ter supplies, and many other areas vital to economic and
social well being. While certain impacts may in the nearer
term prove beneficial to some, in the long-term, the effects
will be largely detrimental.
Carbon dioxide emissions from agriculture are small;
but other important GHGs are emitted from agriculture.
Agriculture accounts for about 60% of all nitrous oxide,
mainly from fertilizer use and about 50% of methane
mainly from natural and cultivated wetlands and enteric
fermentation. Methane and nitrous oxide emissions are
projected to further increase from 35 to 60% by 2030,
driven by growing nitrogen fertilizer use and increased
livestock production in response to growing food demand.
Changes in climate can be expected to have significant
impacts upon crop yields through changes in both tem-
perature and moisture. As climate patterns shift, changes
in the distribution of plant diseases and pests may also
have adverse effects on agriculture. At the same time, ag-
riculture proved to be one of the most adaptable human
activities to varied climate conditions (Mendelsohn et al.,
2001). Many investments are relatively short-term and
crops and cultivars can be quickly changed to suit new
conditions. For these reasons, agriculture at the global
level can probably adapt to a moderate amount of global
warming up to 2.5OC above current levels, assuming no
dramatic change in climate variability. Crops in low lati-
tudes (tropical and sub-tropical) are more often close to
their limits of heat tolerance, while growing conditions are
likely to improve in higher latitudes (temperate), where
agriculture might gain in competitive advantage. As in
other sectors, adaptive capacity is likely to be a major fac-
tor in determining the relative distribution of adverse im-
pacts.
The purpose of mitigation and adaptation measures is
Climate change and agriculture: Adaptation and mitigation stategies
B. VENKATESWARLU AND ARUN K. SHANKER
Central Research Institute for Dryland Agriculture, Santosh Nagar, Hyderabad, Andhra Pradesh 500 059
ABSTRACT
Changes in climate can be expected to have significant impacts on crop yields through changes in
temperature and water availability. The purpose of mitigation and adaptation measures is therefore to attempt a
gradual reversal of the effects caused by climate change and sustain development. There are several mitigation
and adaptation practices that can be effectively put to use to overcome the effects of climate change with
desirable results. These methods fall into the broad categories of under crop/cropping system-based
technologies, resource conservation-based technologies and socio-economic and policy interventions. These
measures are discussed to suggest effective strategies among them to combat climate change with specific
reference to India.
Key words:
Agroforestry, Carbon, Food insecurity, Intercropping, Pollutants, Rainfed farming, Rice fields,
Zero tillage

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June 2009] CLIMATE CHANGE AND AGRICULTURE 227
therefore to attempt a gradual reversal of the effects
caused by climate change and sustain development under
the inescapable effects of climate change. Here is it impor-
tant to note and understand the subtle difference between
mitigation and adaptation. Mitigation and adaptation are
related to the temporal and spatial scales on which they are
effective. The benefits of mitigation activities carried out
today will be evidenced in several decades because of the
long residence time of greenhouse gases in the atmo-
sphere, whereas the effects of adaptation measures should
be apparent immediately or in the near future (Kumar and
Parikh, 2001). Besides, mitigation has global in addition
to local benefits, whereas adaptation typically takes place
on a local or regional scale.
Vulnerability to food security has (difficult phase in)
grown global. Global and local food security vulnerability
patterns will be modified by climate change. Small-scale
rainfed farming systems, pastoralist systems, inland and
coastal fishing and aquaculture communities and forest-
based systems are particularly vulnerable to climate
change. It is imperative to improve preparedness to future
and uncertain impacts through preventive and planned
adaptation and innovation, technical adaptation measures
range from change in production systems like adjusting
planting or fishing dates, rotations, multiple cropping/spe-
cies diversification, crop-livestock pisciculture systems,
agroforestry investing in soil, water and biodiversity con-
servation and development by building soil biomass, re-
storing degraded lands, rehabilitating rangelands, harvest-
ing and recycling water, planting trees, developing adapted
cultivars and breeds, protecting aquatic ecosystems to
maintain long-term productivity. Adaptation measures also
take account of establishing disaster risk management
plans and risk transfer mechanisms, such as crop insurance
and diversified livelihood systems (Reilly and John, 1996).
Mitigation options include carbon sequestration in agricul-
ture and forestry. Mitigation of climate change is a global
responsibility. Agriculture, forestry, fisheries/aquaculture
provide in principle, a significant potential for greenghouse
gases mitigation. The IPCC estimates that the global tech-
nical mitigation potential for agriculture will be between
5,500 and 6,000 Mt CO2-equivalent per year by 2030,
89% of which are assumed to be from carbon sequestra-
tion in soils. The potential benefits of carbon sequestration
are: (i) Mitigation is done when CO2 is removed from the
atmosphere; ii) Adaptation is achieved when higher organic
matter levels in soil increase agroecosystem resilience and
iii) Income generation and livelihood is sustained when
improved soil fertility leads to better yields.
New scope is foreseen in increasing carbon sinks in soil
and in above- and below-ground biomass, and thus con-
tributing to soil carbon sequestration under the post-2012
climate change regime by organic agriculture and conser-
vation agriculture.
Adaptation and mitigation through improved
technologies
The twin pillars under mitigation and adaptation are
strategies (i) mitigation and adaptation through novel tech-
nologies in crop production and management under pro-
jected climate change scenario and (ii) sound governmen-
tal policy and political will to overcome the projected ill
effects of climate change in agriculture.
The first is by successful manipulation of the direct
effects of climate change on grain crops, viz. reduction in
duration, embryo abortion, spikelet sterility, effects on
grain number and grain size, anthesis interval etc. The
strategy involved here is the efficient use of conventional
breeding and molecular/ mutation breeding by the use of
biotechnological tools including marker assisted selection,
whole genome expression analysis and its subsequent elu-
cidation and gene finding by bioinformatics. The indirect
effects, viz. decline in water resources, increased pests and
disease incidence, loss of soil organic carbon should be
tackled by conservation and efficient use of water, inte-
grated pest management and conservation farming.
Crop/cropping system based technologies
These will be mainly centered on promoting the culti-
vation of crops and varieties that fit into new cropping
systems and seasons, development of varieties with
changed duration that can overwinter the transient effects
of change, release of varieties for high temperature,
drought and submergence tolerance, evolving varieties
which respond positively in growth and yield to high CO2.
Besides varieties with high fertilizer and radiation use ef-
ficiency and also novel crops and varieties that can toler-
ate coastal salinity and salt water inundation are needed.
Agricultural biodiversity and crop germplasm explora-
tion for favorable traits is an important area that needs to
be tapped to the fullest extent. Seeds, plants and plant
parts exhibiting tolerance to temperature, water and other
atmospheric stresses caused by climate change needs to
collected and conserved to aid crop breeding research. A
thorough revisit and re-evaluation of all the wild relatives,
land races, extant varieties, modern varieties and breeding
stocks could help in unraveling previously unknown or
ignored traits than could prove more useful in the present
scenario. Genetic resources could well prove to be the
most important cost effective basic raw material which
will allow agriculture to adapt to climate change. In India,
considerable progress has been made in the genetic dissec-
tion of flowering time, inflorescence architecture, tem-
perature, and drought tolerance in certain model plant sys-

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228 VENKATESWARLU AND SHANKER [Vol. 54, No. 2
tems and by comparative genomics in crop plants.
CRIDA, Hyderabad has come out with a transformed Sor-
ghum bicolor L. Moench cv. SPV462 with the mtlD gene
encoding for mannitol -1- phosphate dehydrogenase from
E.coli with an aim to enhance tolerance to water deficit
and NaCl stresses (Maheswari et al., 2006). Germination
potential of these transgenic seeds was several folds higher
when challenged with salt and water stresses. In addition,
they have remarkably robust root system in terms of root
biomass and length. Strategies for genetic enhancement of
heat tolerant genotypes especially in pulses by identifying
and validating markers for high temperature tolerance
coupled with yield potential is one of the key technologi-
cal advances that can prove to be a significant strategy for
adapting to climate change. An additional strategy is to
take advantage of faster growth under higher tempera-
tures, the new varieties, especially of the rabi cropping
season should have characteristics of early flowering
(photo- and temperature-insensitivity, but development-
related onset of flowering) and early maturity and high
produce.
Improved and novel agronomic and crop production
practices like adjustment of planting dates to minimize the
effect of high temperature increase-induced spikelet steril-
ity can be used to reduce yield instability, by avoiding
flowering to coincide with the hottest period (Gadgil,
1995) . Adaptation measures to reduce the negative effects
of increased climatic variability as normally experienced
in arid and semi-arid tropics may include changing the
cropping calendar to take advantage of the wet period and
to avoid extreme weather events during the growing sea-
son. Crop varieties that are resistant to lodging may with-
stand strong winds during the sensitive stage of crop
growth. In addition, improved crop management through
crop rotations and intercropping, integrated pest manage-
ment, supplemented with agroforestry and afforestation
schemes will be an important component in strategic ad-
aptation to climate change in India. In grazing lands, pas-
ture improvement is essential to combat impeding changes
through planned grazing processes, enclosures for recov-
ery, or enrichment planting.
Intercropping is an efficient strategy that can be fol-
lowed with desirable outcome in the present climate
change scenario. Grain-legume intercrops have many po-
tential benefits such as stable yields, better use of re-
sources, weeds, pest and disease reductions, increased
protein content of cereals, reduced N leaching as com-
pared to sole cropping systems. Establishment of seed
banks are of crucial importance in highly variable and
unpredictable environments. This facility will provide a
practical means to re-establish crops obliterated by major
disasters and extreme climate events. This will also help in
plant community dynamics, as differential plant germina-
tion strategies to buffer against inter-annual variability in
growing conditions.
The promotion of scientific agroforestry forms a key
component in the war against climate change.
Agroforestry systems buffer farmers against climate vari-
ability, and reduce atmospheric loads of greenhouse gases.
Agroforestry can both sequester carbon and produce a
range of economic, environmental, and socio-economic
benefits. For example, trees in agroforestry systems im-
prove soil fertility through control of erosion, maintenance
of soil organic matter and physical properties, increased N
accretion, extraction of nutrients from deep soil horizons,
and promotion of more closed nutrient cycling.
Resource conservation-based technologies
The key resource conservation-based technologies are
in situ moisture conservation, rainwater harvesting and
recycling, efficient use of irrigation water, conservation
agriculture, energy efficiency in crop production and irri-
gation and use of poor quality water. The suggested strat-
egies are: characterization of bio-physical and socio-eco-
nomic resources utilizing GIS and remote sensing; inte-
grated watershed development; developing strategies for
improving rainwater use efficiency through rainwater har-
vesting, storage, and reuse; contingency crop planning to
minimize loss of production during drought/flood years
(Kapoor, 2006). Zero tillage (ZT) has effectively reduced
the demand for water in rice-wheat cropping systems in
more than 1 million ha of area in the Indo-Gangetic Plains.
With ZT technology, farmers can realize higher yields and
reduce production costs. In addition, ZT has a direct miti-
gation effect as it converts the green house gases like CO2
into O2 in the atmosphere and carbon, and enriches soil
organic matter. Bed-planting is widely adopted in the Indo-
Gangetic Plains, proved to be a successful conservation
technology. The main advantages are: increased water
use efficiency, reduced water logging, better access for
inter-row cultivation, weed control and banding of fertil-
izers, better stand establishment, less crop lodging and re-
duced seed rates.
In coastal salinity, the Doruvu/Kottai technology for
managing seawater intrusion in coastal areas was practised
effectively in Andhra Pradesh and Tamil Nadu in India.
This mainly involves digging of deep (upto 6 m) open
wells, which allows horizontal flow of underground water
enabled in to the well through pipes. This technology
helps in increased fresh water storage in comparatively
lesser area giving more water to pump and irrigate crops.
System of Rice Intensification (SRI) has key benefits
under the present climate situation. This technology pri-
marily consists of keeping the rice fields moist rather than

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continuously saturated, thereby minimizing anaerobic con-
ditions, and improving root growth and diversity of aero-
bic soil organisms; rice plants are spaced optimally to per-
mit more growth of roots and canopy and to keep all
leaves photosynthetically active; and rice seedlings are
transplanted when young with two leaves, quickly, shallow
and carefully, to avoid trauma to roots and to minimize
transplant shock. SRI offers a potential strategy to counter
climate related risk because it uses less water. The resis-
tance of SRI plants to lodging caused by wind and/or rain,
given their larger root systems and stronger stalks, is a
useful trait for extreme floods. SRI method reduce the
agronomic and economic risks that farmers face with the
advent of climate change.
Integrated Nutrient Management (INM) and Site-Spe-
cific Nutrient Management (SSNM) also have the poten-
tial to mitigate effects of climate change. Demonstrated
benefits of these technologies are; increased rice yields
and thereby increased net CO2 assimilation, 30-40% in-
crease in nitrogen use efficiency. This offers important
prospect for decreasing greenhouse gas emissions linked
with N fertilizer use in rice systems. It is critical to note
here that higher CO2 concentrations in future will result in
temperature stress for many rice production systems, but
will also offer a chance to obtain higher yield levels in
environments where temperatures are not reaching critical
levels. This effect can only be tapped under sufficient in-
tegrated and site directed nutrient supply particularly nitro-
gen (N). Phosphorus (P) deficiency, for example, not only
decreases yield, but also triggers high root exudation and
increases CH4 emissions. Judicious fertilizer application, a
principal component of SSNM approach, thus has 2-fold
benefit i.e. reducing GHG emissions; at the same time
improving yields under high CO2 levels. One of the key
emerging technologies to reduce GHG emissions from
paddy fields is the use of zymogenic bacteria, acetic acid
and hydrogen-producers, methanogens, CH4 oxidizers, and
nitrifiers and denitrifiers in rice paddies which help in
maintain the soil redox potential in a range where both N2O
and CH4 emissions are low (Hou et al., 2000). The appli-
cation of urease inhibitor, hydroquinone (HQ), and a nitri-
fication inhibitor, dicyandiamide (DCD) together with urea
also is an effective technology for reducing N2O and CH4
from paddy fields. Use of neem-coated urea is another
simple and cost effective technology which can be prac-
tised in the entire South Asia by small farmers. Promotion
of integrated farming systems for marginal and small
farmers will also be a viable and effective alternative in
combating climate change. Multiple-enterprise agriculture
wherein crop, livestock, poultry, fish farming and trees in
a single unit of land will minimize risk.
Policy interventions
Apart from the use of technological advances to com-
bat climate change related impacts on crop production,
there has to be sound policy framework and strong politi-
cal will on the part of the government to effectively battle
climate change. A sound policy framework should ad-
dress the issues of redesigning social sector with focus on
vulnerable areas/ populations, introduction of new credit
instruments with deferred repayment, liabilities during ex-
treme weather events, and weather insurance as a major
vehicle to transfer risk. Governmental initiatives should be
undertaken to identify and prioritize adaptation options in
key sectors, viz. storm warning systems, water storage
and diversion, health planning and infrastructure needs.
Focus on integrating national development policies into a
sustainable development framework that complements ad-
aptation should accompany technological adaptation meth-
ods. Emphasis should also be given on tapping financial
resources to strengthen adaptation efforts within coun-
tries. Besides the role of local institutions in strengthening
capacities e.g. SHGs, banks and agricultural credit societ-
ies should be promoted. Role of community institutions
and the role of private sector in relation to agriculture
should be a matter of policy concern. There should be
political will to implement economic diversification in
spreading diverse livelihood strategies, migrations and fi-
nancial mechanisms (Schneider et al., 2007). Policy initia-
tives in relation to access to banking, micro-credit/insur-
ance services before, during and after a disaster event,
access to communication and information services is im-
perative in the envisaged climate change scenario.
Some of the key policy initiatives, to be considered, are:
(i) mainstreaming adaptations by considering impacts in
all major development initiatives. (ii) facilitate greater adop-
tion of scientific and economic pricing policies, especially
for water, land, energy and other natural resources. (iii)
consider financial incentives and package for improved
land management and explore CDM benefits for mitigation
strategies and (iv) establish “Green Research Fund” for
strengthening research on adaption, mitigation and impact
assessment.
It is concluded that even though climate change in India
is a reality and impending negative consequences are pre-
dicted, a more certain assessment of impacts and vulner-
abilities and a comprehensive understanding of adaptation
options across the full range of warming scenarios, sec-
tors and regions would go a long way in preparing the
nation for climate change.
The following researchable issues are identified for
future:
(i) Breeding for improved crop varieties with specific

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230 VENKATESWARLU AND SHANKER [Vol. 54, No. 2
reference to growth and flowering phenology, photo
sensitivity/insensitivity, stability in response to inputs
viz., lodging resistant, optimum tillering, harvest in-
dex etc.
(ii) Evolving efficient water and soil management prac-
tices in addition to identification of crops and varieties
with high water use efficiency, dry matter conver-
sion ratio, positive response to temperature extremes
and elevated CO2.
(iii) Identifying new intercropping and novel farming sys-
tem combinations including livestock and fisheries,
which can withstand predicted climate change situa-
tions and can be economically viable.
(iv) Identifying cost effective methods for reducing
greenhouse gas emission from rice paddies and also
from cropping systems with livestock components.
(v) Promoting conservation agriculture practices espe-
cially in water harvesting, nutrient, pest and disease
management.
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