Environmental Engineering Reference
In-Depth Information
TABLE 1 Relationship of Atmospheric Concentrations of Carbon Dioxide to Temperature
Stabilization CO
2
Range and Best Estimate
-Equivalent Concentration (ppmv):
Equilibrium Global
Average Warming (°C)
320
340
380
1
370
430
540
2
440
540
760
3
530
670
1060
4
620
840
1490
5
Note:
Green
and
red
numbers represent low and high ends of ranges, respectively;
black bolded
numbers
represent best estimates.
The report calculates the “likely” range (66% chance) of atmospheric concentrations
associated with various degrees of warming, consistent with model results
1
and roughly
consistent with paleoclimate evidence. There are large uncertainties in
'climate
sensitivity'
—the amount of warming expected from different atmospheric
concentrations of greenhouse gas—the range is 30% below and 40% above the best
estimates.
1
The estimated “likely” range presented in this report corresponds to the range of model results in the
Climate Modelling Intercomparison Project (CMIP3) global climate model archive.
perature increases. This is done by scaling local to global warming and by
“coupled linkages” that show how other climate changes, such as alterations
in the water cycle, scale with temperature.
There is now increased confidence in how global warming levels of 1°C,
2°C, 3°C etc. (for °F conversion, see Figure Syn.2) would relate to certain
future impacts. This report lists some of these effects
per degree (
°
C) of
global warming
(see Figure Syn.3), including:
• 5-10 percent changes in precipitation in a number of regions
• 3-10 percent increases in heavy rainfall
• 5-15 percent yield reductions of a number of crops
• 5-10 percent changes in streamflow in many river basins
worldwide
