Vital GEO Graphics

Tackling the Issue

Paths to reach a 400 ppm CO -equivalent greenhouse gas concentra- tion target (Kyoto gas emissions plus land use CO ) 2

2

Climate change presents a threat whose precise magnitude is unknown but is potentially massive. The impact of decisions made now will continue to be felt for decades or centuries. Various analysts have identified a 2°C increase in the global mean temperature above pre-industrial levels as a thresh- old beyond which climate impacts become signifi- cantly more severe and the threat of major, irrevers- ible damage becomes more plausible. Staying under the 2°C threshold will require very stringent measures on greenhouse gas emissions, and the longer the delay in implementation, the steeper the reduction trajectory required. Various policies and measures to mitigate climate change have been implemented worldwide. They make up a crucial first wave in efforts to limit green- house gas emissions and to ultimately switch from the carbon intensive economies. Many important actions have been taken but the net effect is still woefully inadequate. Mainstreaming climate concerns in development planning is urgent, especially in sectors such as en- ergy, transport, agriculture, forests and infrastructure development, at both policy and implementation levels. Adaptation to anticipated climate change is now a global priority.

~3.6%/y ~2.6%/y ~5.4%/y Maximal reduction rate of

D ownload G raphic 2

Emissions relative to 1990 level (%)

160

140

120

100

80

60

40

20

0

2000

2010

2020

2030

2040

2050

1990

o

Notes: The risk of overshooting a 2 threshold increases rapidly if greenhouse gas concentrations are stabilized much above 400 ppm CO -equivalent in the long term. Path 2 postpones the peak in global emissions until about 2020, but requires subsequent annual emissions reductions at an exceptionally challenging pace of more than 5 per cent/year. 2

Source: Den Elzen and Meinshausen 2005

The clearance of forested land and its subsequent use for cattle and crop production, releases carbon stored in the trees and soils, and depletes its potential as a CO 2 sink. Credit: Ngoma Photos

17 CL IMAT E CHANGE