The probable impacts of climate change on poverty - UNDP

4.1 Climate Change - Global Context
<strong>The</strong> Fourth Assessment Report (AR4) <strong>of</strong> the Intergovernmental Panel on Climate Change had unequivocally
confirmed the warming <strong>of</strong> <strong>climate</strong> system and linked it directly to human activity. <strong>The</strong> effects <strong>of</strong> warming were
already grave and they were growing. <strong>The</strong> global average surface temperature has already increased by 0.74oC during last 100 years; sea level rose at an average rate <strong>of</strong> 1.8 mm per year over 1961 to 2003; mountain glaciers
and snow cover have declined on average in both hemispheres; eleven <strong>of</strong> the last twelve years (1995-2006) rank
among the 12 warmest years. Continued greenhouse gas emissions at or above current rates would cause
further warming and induce many <strong>change</strong>s in the global climatic system during the 21st century that would very
likely be larger than those observed during the 20th century.
<strong>The</strong> AR4 stated that for the next two decades, a warming <strong>of</strong> about 0.2˚C per decade is projected for a range <strong>of</strong>
Special Report on Emission Scenarios (SRES). Even if the concentrations <strong>of</strong> all greenhouse gases and aerosols had
been kept constant at year 2000 levels, a further warming <strong>of</strong> about 0.1˚C per decade would be expected.
Expected <strong>change</strong>s in global mean temperature is likely to increase by 1.1 to 6.4˚C from 1990 to 2100 while water
availability will increase in moist tropics and high latitudes and decrease in mid-latitudes and semi-arid low
latitudes. Sea levels are likely to rise in the range <strong>of</strong> 22-34 cm between 1990 and the 2080s. Future tropical
cyclones, typhoons, and hurricanes will become more intense, with larger peak wind speeds and heavy
precipitation.
4.1.1 Impacted Sectors: Freshwater Resources
<strong>The</strong> Fourth Assessment Report <strong>of</strong> the IPCC projected that by mid-century, annual average river run<strong>of</strong>f and water
availability are projected to increase by 10-40% at high latitudes and in some wet tropical areas, and decrease by
10-30% over some dry regions at mid-latitudes and in the dry tropics, some <strong>of</strong> which are presently water-stressed
areas. Drought-affected areas are likely to increase to a considerable extent. Heavy precipitation events, which
are very likely to increase in frequency, will augment flood risk. In the course <strong>of</strong> this century, water supplies stored
in glaciers and snow cover are projected to decline, reducing water availability in regions supplied by melt water
from major mountain ranges, where more than one-sixth <strong>of</strong> the world population currently lives.
4.1.2 Ecosystem
<strong>The</strong> resilience <strong>of</strong> many ecosystems is likely to be exceeded by this century by an unprecedented combination <strong>of</strong>
<strong>climate</strong> <strong>change</strong>, associated with disturbances (e.g., flooding, drought, wildfire, insects, ocean acidification), and
other global <strong>change</strong> drivers (e.g., land use <strong>change</strong>, pollution, over-exploitation <strong>of</strong> resources). Approximately 20-
30% <strong>of</strong> plant and animal species assessed so far are likely to be at increased risk <strong>of</strong> extinction if increases in
global average temperature exceed 1.5-2.5˚C. For increases in global average temperature exceeding 1.5-2.5˚C
and in concomitant atmospheric carbon dioxide concentrations, there are projected to be major <strong>change</strong>s in the
ecosystem structure and function, species’ ecological interactions, and species’ geographical ranges, with
predominantly negative consequences for biodiversity, and ecosystem goods and services e.g., water and food
supply. <strong>The</strong> progressive acidification <strong>of</strong> oceans due to increasing atmospheric carbon dioxide is expected to have
negative <strong>impacts</strong> on marine shell-forming organisms (e.g., corals) and their dependent species.
4.1.3 Food, Fibre & Forest Product
Crop productivity is projected to increase slightly at mid- to high latitudes for local mean temperature increases
<strong>of</strong> up to 1-3˚C depending on the crop, and then decrease beyond that in some regions. At lower latitudes,
especially seasonally dry and tropical regions, crop productivity is projected to decrease for even small local
temperature increases (1-2˚C), which would increase the risk <strong>of</strong> hunger. Globally, the potential for food
production is projected to increase with increases in local average temperature over a range <strong>of</strong> 1-3˚C, but above
this it is projected to decrease. Increase in the frequency <strong>of</strong> droughts and floods is projected to affect local crop
production negatively, especially in subsistence sectors at low latitudes.
Globally, the potential for food production is projected to increase with increases in local average temperature
over a range <strong>of</strong> 1-3˚C, but above this it is projected to decrease. Regional <strong>change</strong>s in the distribution and
<strong>The</strong> Probable Impacts <strong>of</strong> Climate Change on Poverty and Economic Growth and
the Options <strong>of</strong> Coping with adverse Effect <strong>of</strong> Climate Change in Bangladesh
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