Detailed emissions breakdown

Emission source				tonnes of CO2
		2010	2009	2008	2007	2006
Scope 1 – Stationary combustion
Gas combustion	7,193	4,889	4,537	6,178	N/A
Heating oil combustion	2,182	1,393	1,400	1,547	N/A
Total scope 1 emissions	9,375	6,282	5,938	7,725	2,479
Scope 2 – purchased electricity
Total purchased electricity (gross)	156,749	160,414	135,658	121,648	141,875
Less purchases of:
Renewable electricity1	(25,011)	(23,542)	(20,024)	(5,038)	–
Scope 2 emissions (net)	131,738	136,872	115,634	116,611	141,875
Combined scope 1 and 2 emissions (net)	141,113	143,154	121,572	124,335	144,354
Scope 3 – other indirect emissions
Air travel	85,848	76,073	89,500	92,269	81,733
Other indirect emissions2	34,044	32,884	31,661	32,491	33,913
Total scope 3 emissions	119,892	108,957	121,161	124,760	115,646
Total CO2 emissions (net)	261,004	252,111	242,733	249,095	260,000

Carbon intensity

Emission scope		tonnes of CO2 per person
		2010	2009	2008	2007	2006
Scope 1	0.09	0.06	0.06	0.09	0.03
Scope 2 (net)	1.27	1.39	1.21	1.29	1.79
Scope 3	1.15	1.10	1.27	1.38	1.46
Total (net)	2.51	2.55	2.54	2.76	3.28
Percentage change from base year (net)	-23%	-22%	-22%	-16%	–

Office energy use

		megawatt hours
		2010	2009	2008	2007	2006
Total office energy use	350,724	340,647	284,930	272,545	297,406

¹

When calculating our carbon footprint we rate renewable electricity as zero emissions.

²

We add an additional 15% to our carbon footprint to account for unmeasured impacts, such as couriers and taxis.