Article Type : Review Article
Authors : Toor MD, Rehman F, Adnan M, Kalsoom M and Shahzadi L
Keywords : Environmental fluctuations; Climatic conditions; Abiotic stress; Crop pathology; Food security
In agriculture we can
find a huge amount of literature regarding environmental management and
adoption of technology for sustainable farming. This review article focus on
relationship between environmental changes and their impact on agriculture.
This two-way relation among environmental change and agriculture is gaining
great importance. Environment is the primary determinant for the productivity
of agriculture. Agriculture directly depends on the broader environment and
uses about a 3rd of the world’s land surface. The strength and occurrence of
extreme events will rise by the global warming i.e. water deficient condition,
flood, tornado that would greatly harm the water balance and agriculture
production in upcoming years. Climatic change affects agriculture by emissions
of greenhouse gases such as nitrous oxide, methane and carbon dioxide. The
direct sources of these emissions are use of tillage practices, fossil fuels,
manuring of livestock and use of fertilized agricultural soils in large
proportion. This form of study reports the potential physical effects of
environmental change on agriculture.
According to the most current predictions the
worldwide population is speedily growing and, it is estimated to extent 9.8
million in 2050 and almost 11.2 million in 2100 [1]. One of the most essential
challenges for people in the next era is to generating and providing
sufficient, high value food [2,3]. Moreover, environmental change is the most
serious threat of environment that unfavorably affects the productivity of
agriculture. Systems of plant, and hence yields of crop, are influenced by many
factors which is directly related with environment, and these aspects, such as
temperature and moisture, may act both antagonistically or synergistically with
further factors in yields determination [4]. Worldwide environment has been
fluctuating continuously over millennia but due to increase in anthropogenic
activities the previous few years have perceived a substantial emissions of the
greenhouse gases such as fossil fuel burning, degradation of land, industrial
processes, and removal of forests. Furthermost studies undertake simply
estimate the influence of temperature change on farm yields and little
adaptation [5]. Others permit limited fluctuations in application of
fertilizer, cultivars or irrigation. Asiatic region and the countries which lie
in it are particularly susceptible to the effects of greenhouse gas emission
with increased in concentrations and the prospective increased occurrence and
destruction caused by floods, storms, heavy rains, water scarcities, composed
with potential increase in level of sea disturb the balance of water and
productivity of agriculture [6]. The significances and influence of change in
climate for agriculture tend to be further severe for states with greater
primary temperatures, zones with peripheral or previously degraded areas and
subordinate development levels with little capacity of adaptation. Eventually,
humans’ practices to changing economic and physical conditions and adapted
agricultural systems. Changing crop mixes and institutional arrangements, and
cultivated acreages has been accomplished by adopting new technologies which
including investments in genetic developments. Such type of elasticity is
indicative of major human potential to adapt to change in climatic conditions
[7]. Moreover, many studies show that current activities of agriculture are an
important source of greenhouse gases that are aggravated for the disruption of
climate. Greenhouse gases contain Methane, Carbon Dioxide, water-vapor’s and
Nitrous Oxide which leads to the global warming [8]. The sectors which are
leads to increase in concentration of Greenhouse gases as fractions are 63% by
sector of energy, by agricultural activities 3% by industrial land use 18% by
forest and 3% from the generated waste. The consideration of the scientific
community has been drawn by the environmental problems which are related to
agriculture, which is rotating towards the meaning of sustainable agriculture
without having yet reached consensus [9]. Even though, agricultural practices
could be a source of Greenhouse gases as well as a sink, notably through the
carbon storage in the biomass and in soil organic matter and influenced by
climate change [10]. In developing counties agriculture practices is very
different as compare to developed regions, which leads to the dissimilarities
of contribution of agriculture to change in climatic conditions. Greenhouse
emission from agriculture sector is much more in developing countries because
of the huge number of cattle and insufficient manure management, inappropriate
use of agro-chemicals and mishandling of the land [11]. Furthermore, climatic
change impact turns into more severe in emerging countries due to their
agricultural dependence. In addition, emissions of greenhouse gases are
increasing at a speed of 23 ppm per decade, subsequently in the previous 6.5
million years [12].
Production of agriculture results into the
several environmental problems such as change in climate, loss of biodiversity,
degradation of soil, and pollution of water. Agricultural activities can either
degrade or sustain the environmental conditions has renowned the main negative
effects of agriculture on freshwater and land, as well as the significance of
landscapes that’s belong to agriculture in providing yields for nourishment of
human, maintaining services of ecosystem and supporting the biodiversity [13].
Negative impacts such as forests conversion, grasslands and other habitations
for the use of agriculture, soil quality degradation, soil pollution and water
surface aquifers and seaside marsh land through unsuitable or unnecessary use
of fertilizers and pesticides, substantial crop loss and cattle genetic variety
through the extent of industrial monocultures, decreasing flexibility in the
face of temperature and other fluctuations [14]. Almost 40% of the worldwide
ice-free land is used for the production of agriculture. Land-use change
continuous like deforestation is related with several environmental problems,
specially the decrease in biodiversity and the proclamation of soil carbon into
the atmosphere [15]. Therefore, balancing in the production of food and
environmental goals will gradually involve using land and other resources which
are natural more proficiently. Agricultural activities generate both indirect
and direct emissions [16]. Direct emissions arise from the application of
livestock manure and use of fertilizer on agricultural soil. Although indirect
emissions originate from leaching and overflow of fertilizers, emission from
changes in land-use, consumption of fossil fuels for mechanization,
agro-chemical and transport and production of fertilizer [17,18]. The most
important indirect emissions are the variations in traditional land use and
natural vegetation, including degradation of soil and removal of forests. Land
with agricultural production is an inadequate natural reserve. It is expected
that nearly a 3rd of worldwide arable land has been misplaced due to
pollution and erosion of soil during the previous 40 years [19]. Degradation of
soil usually refers to several processes, such as desertification, erosion,
compaction, salinization, and encroachment of invasive species [20].
Agricultural practices lead to the 30-40% of greenhouse gases emissions through
anthropogenic sources and this share may increase above 80% by 2050.
Increasingly over the centuries, farming processes have grown and become more
effective [21]. But, now with development in technology and new research,
technologists have established the destructive effects that farms have had on
the environmental conditions. Agricultural activity is accountable for 20% of
the total for the worldwide total anthropogenic emissions of carbon dioxide.
According to FAO statement in emerging countries there is a substantial upturn
in the emission of greenhouse gases from 2001-2011 (14%), the growth occurred,
due to a development of total outputs of agriculture [22].
Change in climatic conditions has been forecast to
impact production of agriculture through various indirect and direct pathways.
Availability of water and temperature changes combined with increased deviation
in conditions of weather and more repeated weather episodic events will have a
direct impact on yields of crop [23]. Moreover, agricultural land is degraded
very quickly. [24] For instance, growing temperatures upturn tropospheric such
as ground-level formation of ozone, and enlarged ozone levels cause plants
oxidative stress, which reduces the growth of plant and formation of
photosynthesis. Moreover, the direct effects, leads to temperature increased
may indirectly affect the yield of vegetables and fruit due to decrease the
productivity of labor of farmers, affecting productivity of agriculture [25].
Change in Climatic conditions affects agricultural system in a number of ways
such as through average temperature changes; extremes of climatic conditions
and rainfall with an important impact on erosion of soil like drought, floods,
changes in diseases and pests, changes in amount of carbon dioxide in
atmosphere, changes in the quality of nutrition of some foods, changes in
season of growing, and changes in level of sea [26]. The tropical and
sub-tropical region where many countries lie are more likely to be vulnerable
to warming because of extra raise in temperature that will anguish marginal
balance of water and damage agriculture productivity [27]. Change in climate
increases the agricultural vulnerability zones such as tornadoes, overflows of
water and water scarcities, in turn sensational state to the risk of losses in
socio-economic sector. Change in climatic conditions may aggravate problems of
salinity which in turn impact health through diet and water drinking was of the
view that change in climate has noteworthy impact on friable soil and
traditional systems of farming [28]. Furthermore, fluctuation in pattern of
precipitation and water scarcity can cause important increase in concentrations
of sodium in bodies of freshwater, disturbing irrigation and water drinking
value [29].
Various climatic factors relative to disease should
include an examination of the variability in climate of the location in
question for at least the past 10-20 years. Human knowings about climate and
willingness to use that understanding in societal decision-making change over
the globe [30]. It is possible that climate variations over space is more
essential to human development than climate variations over time. This is
suggested by the fact that regions with the most changing climates are near the
tropics and that countries in these areas are usually less able to deal with
effects of unfavorable weather than that of the countries in temperate regions.
In some countries, the internal changes of yields are greater than those
predicted for other countries over much longer periods of time [31]. Short-term
climate changes may have long-term consequences in some ecosystems like
forests. The impact of change may depend upon the type of variation that
occurs. Particularly, in marginal areas, a large biological effect is caused by
a small change in frequency of extremes. There are large differences between
temperate regions and tropic region with regard to the effect of precipitation
and temperature on agricultural productivity [32]. Rainfall is the main
production-limiting factor in the tropic region: a small variation in timing
and amount of rain can result in high changes in interannual crop yields. In
temperate regions, temperature is most essential in defining the length of the
growing season. The precipitation interacts in a very complex manner with
temperature to influence the crop growth. Any specific climate variation will
affect agriculture in the tropical and temperate regions in various ways [33].
Impact of climatic variation crop pathology
Wide number of studied have been made on how climate
affects plant diseases. It has been concerned with day-to-day weather
conditions rather than with year-to-year climatic variability [34]. A variation
in prevailing climatic conditions or a variation in climatic variability may
alter plant disease development by affecting: [35]
·
The speed of development
and number of pathogen or vector generations
·
the geographical
distribution of the host, pathogen, or vector, particularly on the margins of
their respective distributions
·
The dispersal of the
pathogen or vector with respect to synoptic-scale movement
·
The host-pathogen
interactions that have evolved into a functional system
·
The control of disease
Environmental changes can also affect host-pathogen
interactions by modifying their courses of development with respect to each
other. It is also possible that climatic variations could reduce a crop's
vulnerability by putting its development and that of the pathogen out of phase with
each other [36].
Food security and climate change:
a conceptual framework
Food systems present in biosphere, along with all other changes of human activity. Some of the significant manifestation in the biosphere that are expected be from global warming will occur in the more distant future, as a consequence of changes in average weather conditions [37]. The most likely scenarios of climate changes indicate that increases in weather variability and incidence of extreme weather events will be significant now and in the nearby future. The projected increase in mean temperatures and precipitation will not manifest via constant gradual changes, but will instead be experienced as increased duration, frequency and intensity of hot spells and precipitation events [38]. Whereas the annual occurrence of hot days and maximum temperatures are expected to increase in everywhere in the globe, the mean global increase in precipitation is not expected to be uniformly spread around the world. In general, it is expected that wet regions will become wetter and dry regions more dryer. A conceptual framework on climate change and food security interactions has been developed to highlight the variables defining the food and climate systems for this analysis [39]. The climate change and food security framework expose how climate change affects food security outcomes for the four main components of food security in various direct and indirect ways. These four main components of food security are [40].
Climate change variables greatly influence the
biophysical factors, like plant and animal growth, biodiversity, water cycles
and nutrient cycling, and the ways in which these are managed through
agricultural practices and land use for production of food. However, climate
variables also have an effect on physical/human capital which indirectly
influence the economic and socio-political factors that govern food access and
utilization and can also threaten the stability of food systems [41]. All of
these impacts change themselves in the ways in which food system activities are
done. The framework proves how adaptive adjustments to food system activities
are needed all along the food chain to cope with the impacts of climate
manifestations. The climate change variables that are considered in the CCFS
framework are as follow; [42]
1. The
CO2 fertilization effects of higher amount greenhouse gas
concentrations in the atmosphere
2. Increased
rate of mean, maximum and minimum temperatures;
3. Gradual
manifestation in precipitation: increase in the frequency, duration and
intensity of droughts;
4. Manifestation
in the timing, intensity duration and geographic location of rain and snowfall
5. Increase
in the intensity and frequency of storms and floods
6. Greater
seasonal weather variability and changes in start and end of growing seasons
Evidence
indicates that the frequent and intense extreme weather events like droughts,
heavy storms, heat and cold waves and floods marking rise in sea levels and
increasing irregularities in seasonal rainfall patterns bring floods are
already having immediate effects on not only food production, but also
incidence of food emergencies, food distribution infrastructure, human health
and livelihood assets in both rural and urban areas [43]. In addition, less
immediate impacts are expected to be from gradual manifestation in mean
temperatures and rainfall. These manifestations affect the suitability of land
for various types of crops and pasture; the health and productivity of forests;
the incidence and vectors of different types of pests and diseases; the
distribution, productivity and community composition of marine resources; the
biodiversity and ecosystem functioning of natural habitats and the availability
of good-quality water for crop, livestock and inland fish production [44].
Arable land is likely to be lost owing to increased aridity and also associated
salinity, groundwater depletion and sea-level rise. Food systems will be
affected by internal and international migration, civil unrest triggered by
climate change and resource-based conflicts [45].
The study evaluates the impact of global climate
change on agricultural major crops production. Climate is the primary
determinant of agricultural productivity. From this extensive review, it is
concluded that globally, climate change has relationship with agriculture in
one or another way. ?ere are also indirect emitters such as land use change;
leaching of fertilizers; use of fossil fuels for mechanization; transport and
agro-chemical and fertilizer production that have adverse impacts on
Agriculture due to climatic variations.