The Case for Contraction and Convergence
39
Mauna Loa, Hawaii, United States In Situ (Obs) Data (Sample Intake Height: 3397 masl)
400
Data provided by: Kirk Thoning (GMD) March 25, 2006
MLO (19N; 155W; 3397 masl)
CO2 (µmol mol–1)
380
360
340
(Preliminary Data shown in GRAY)
320 1970
390 386
1980
1990 Year
2000
2010
NOAA ESRL GMD – Custom Graph Data provided by: Thomas J. Conway (GMD) March 25, 2006
MLO (19N; 155W; 3397 masl) Network Flask Data (Sample Intake Height: 3397 masl)
CO2 (µmol mol–1)
382 378 374 370 366 362 358 354 (Preliminary Data shown in GRAY)
350 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Year Figure 8 CO2 measured at Mauna Loa Observatory.
now varying extent to which these are increasingly retained there. The relationship between emissions and atmospheric concentration over this period has seen on average a constant fraction of each year’s emissions remaining airborne. This so-called ‘Constant Airborne Fraction’ has until recently, been 50 per cent; i.e. 50 per cent of
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