Climate Change (Impacts on Society - Consequences ( Land use human…
Impacts on Society - Consequences
Crops may depend on specific mix of soil, temperatures and rainfall
patterns that could be disrupted by global warming.
• Regional Impacts
More extreme weather events are likely, floods in some areas; droughts in
others. Most likely will affect LDCs more than MDCs.
Land use human settlements
• Modest rise in sea level could devastate coastal settlements in which half of
human population lives.
Farmland lost, salinity would increase
• Rising global temperatures could threaten water for millions; stream flows
would be reduced, pollution would be increased.
• Planning uncertainty
• Perpetual, unpredictable change could lead to a treadmill of constant adjustment.
• Threats to human health could include heat stress, increase in tropical diseases, increased energy consumption , losses in tourism, loss of food and
forests could lead to significant social unrest
Some Ambiguities in the
Evidence for Climate Change
Climate may not change in a linear fashion.
The role of the oceans is not fully understood
but is likely to be large.
Greenhouse gas concentration and
temperature fluctuation correlation works for geological history but not as much for
shorter time frames.
Hard to estimate impact of vegetation and
Interactions and feedbacks between
temperature change and cloud formation are
not clear. Will there be more or fewer
clouds? More or less reflectivity?
Risk of Climate Change
• First the consequence of climate change needs to be understood
• The 2°C limit is often used
• An optimistic limit aimed at providing a benchmark or common goal
Other greenhouse gases
• Produced by bacterial fermentation
It’s influence may be significantly under appreciated
CFCs – now banned, due to Ozone depletion
HFCs – Talks of banning it
A measure of how much
an agent is affecting
earth’s energy balance
Likelihood of Impacts
• Various uncertainties muddy the water
• Predictions of consequence rely on General Circulation Models
Important Graphs 3-16