Geoscience Reference
In-Depth Information
climatic events. Climate change enhances the spreading of
pests and diseases as well. Climate change may also cause
increased exposure to heat stress, changes in rainfall patterns,
greater leaching of nutrients from the soil during intense rains,
greater erosion due to stronger winds and more wildfires in
drier regions. All these result in lower yield. Moreover, due to
climate change, many wild species of food crops would become
extinct. For example, one-fourth of all wild potato species are
predicted to die out within 50 years, which could make it dif-
ficult for future plant breeders to ensure that commercial variet-
ies can cope with climate change.
One of the positive impacts of the increased CO
2
level may
be the increased photosynthesis which in turn is expected to
contribute to enhanced biomass production. On the other, the
increased temperature associated with the increased level of
CO
2
would have negative physiological impacts leading to
increased photorespiration.
The impact on population structure
The genetic structure
of a normal random mating population is explained by the
Hardy-Weinberg principle which states that the gene and gen-
otype frequencies in a large random mating population remain
constant from generation to generation provided there is no
specific disturbing forces viz., mutation, migration, selection
and random genetic drift, etc. Climate change can disrupt the
equilibrium by inducing migration of gene and genotype from
one population to other, induce mutation (radiation and chem-
ical) creating new allele and put differential selection pressure
on population.
Indirect impacts
of climate
change on
biodiversity
Although direct impacts are easily observable as well as
well predicted, there are certain indirect impacts of climate
change on biodiversity that are of equal importance. When
climate change directly alters symbiotic fungi associated
with plant root system, it will indirectly cause a change in
that plant's natural distribution. Another example of indirect
impact is—a new grass may spread into a region that results
in altering the fire regime and ultimately changes the species
composition.
All these indirect impacts are very difficult to predict.
Impact of
climate change
on specific
ecosystems
Impact on forest ecosystems
a.
Tropical montane forests
: As a result of a rise in tem-
peratures, tropical montane forests lose humidity or face