Agriculture Reference
In-Depth Information
livelihood security in times of catastrophic
incidents both natural and human driven.
While short-term mitigation measures would
always demand immediate attention, the com-
plexities of abiotic stress on crops and livestock
in the long term would require intensive research
to effectively address the adaptation processes
required for making our production systems
resilient to climate change.
information about the nature of the evidence and
what can be done in response to a changing cli-
mate. This topic provides some of that much-
needed information collected from some of the
world's leading climate scientists.
The terms “weather” and “climate” are fre-
quently considered to be interchangeable, but
weather and climate refer to different things.
Weather is the brief, rapidly changing condition
of the atmosphere at a given place and time, infl u-
enced by the movement of air masses. Climate, on
the other hand, should more accurately be the
term applied to the average weather conditions
over longer periods of years to decades.
One may often hear mention of “climate vari-
ability” and “climate change” together. They are
different facets of climate. Climate variability
refers to the year-to-year variations, or noise, in
the average conditions - meaning that consecutive
summers, for example, will not all be the same,
with some cooler and some warmer than the long-
term average. Climate change refers to any long-
term trends in climate over many years or decades,
around which climate variability may be evident
year on year. Hence, a single warmer or cooler
year on its own is not a suffi cient evidence to
assert that climate is changing, but systematic
changes in average conditions over many years do
provide evidence of a changing climate.
The earth's climate has always changed, alter-
nating between long periods of warm (intergla-
cial) and cool (glacial) conditions, cycling over
tens to hundreds of thousands of years. These
changes are driven by both external infl uences
and dynamics internal to the earth system. Key
external infl uences include fl uctuations in the
amount of energy emitted by the sun and changes
in the earth's orbit and axial tilt that affect the
intensity and distribution of the sun's energy
across the earth. Internal infl uences on climate
include changes in the surface refl ectivity due to
the presence or absence of ice, changes in atmo-
spheric composition of GHGs, variations in ocean
currents, drifting continents, the cooling effect of
volcanic dust, and other geological processes.
UNFCCC defi nes climate change as “a change
of climate that is attributed directly or indirectly
1.1
What Is Climate Change?
Our atmosphere is full of invisible gases, some of
which are greenhouse gases (GHGs). GHGs insu-
late the earth. They trap the sun's heat and keep
our planet warm enough to sustain life. Some
GHGs in our atmosphere do exist naturally. But a
large portion of the GHGs in our atmosphere
today have been, and continue to be, created by
humans. This means that more of the sun's heat is
being trapped than the earth actually needs. In
fact, too much heat is being trapped, and the
planet is warming too much. This is what is
known as “global warming.” Global warming is
affecting weather patterns all over the world, and
this effect is what is known as “climate change.”
A region's climate means the usual weather
patterns and conditions of a region. So, a change in
weather patterns and conditions is a change in cli-
mate. The world's weather patterns are changing.
This includes temperature changes (warming in
some places and cooling in others) and altered
rainfall patterns, as well as more frequent occur-
rences of hazardous weather events like heavy
spring rains and heat waves. Changing climates
pose risks to the health and safety of people, wild-
life, forests, farms, and water supplies. Hence, it is
so important for the government, farms, and food
processing businesses to be aware of the causes of
climate change and take corrective action. We all
have a role to play in reducing GHG emissions.
Climate change is one of the greatest ecologi-
cal, economic, and social challenges facing us
today. The scientifi c evidence that human activi-
ties are contributing to climate change is compel-
ling, but society is increasingly seeking
 
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