High Programmer > Alan De Smet > Rants > USPIRG's Bad Carbon Dioxide Statistics

USPIRG's Bad Carbon Dioxide Statistics

The individual states of the United States of American are arbitrary things. Their sizes, shapes, and populations are the result of a mixture of history and geography. They have nothing to do with efficiency. So any study that draws conclusions about things on a state-by-state level, ignoring population and geography, is almost certainly doing something wrong. It's an easy mistake to make, since data is often only available at the state level. But it's sloppy at best and outright misleading at worst.

A stunning example of this sloppiness is USPIRG's "The Carbon Boom: State and National Trends in Carbon Dioxide Emissions Since 1990" (PDF). They have a table of "Top 10 States for Carbon Dioxide (CO₂) Emissions, 2004." That table is circulating around, mostly by people interested in showing how terrible Texas is. (I first became aware of in "Dirty Texas Wins 2004 CO2 Polluting Title" at the Threat Level blog.)

Here's a copy of the table in question:

Rank	State	2004 CO₂ Emissions (mmt)
1.	Texas	659.0
2.	California	385.4
3.	Pennsylvania	276.6
4.	Ohio	261.8
5.	Florida	255.4
6.	Indiana	236.2
7.	Illinois	233.8
8.	New York	212.8
9.	Louisiana	190.0
10.	Michigan	185.8

Wow, Texas sure looks awful, right? Time to dump on Texas, those savages who are ruining the world! I have no love lost for the Lone Star state, but they don't deserve this abuse.

Well, USPIRG did put the full table of data in their document. Add in the populations of the states and you can calculate CO₂ emissions per person, which is far more telling:

Rank	State	Million metric tons CO₂¹	Population²	Metric tons CO₂ per person
1	WY	63.50	509,294	124.68
2	ND	49.20	636,677	77.28
3	AK	45.40	663,661	68.41
4	WV	112.40	1,816,856	61.87
5	LA	190.00	4,523,628	42.00
6	IN	236.20	6,271,973	37.66
7	MT	34.90	935,670	37.30
8	KY	150.40	4,173,405	36.04
9	AL	141.20	4,557,808	30.98
10	NM	58.10	1,928,384	30.13
11	TX	659.00	22,859,968	28.83
12	KS	76.10	2,744,687	27.73
13	OK	98.10	3,547,884	27.65
14	IA	79.10	2,966,334	26.67
15	UT	65.00	2,469,585	26.32
16	NE	42.50	1,758,787	24.16
17	MO	137.90	5,800,310	23.77
18	OH	261.80	11,464,042	22.84
19	AR	62.70	2,779,154	22.56
20	PA	276.60	12,429,616	22.25
21	MS	65.00	2,921,088	22.25
22	TN	125.10	5,962,959	20.98
23	SC	88.10	4,255,083	20.70
24	DE	16.60	843,524	19.68
25	CO	91.40	4,665,177	19.59
26	NV	47.20	2,414,807	19.55
27	MN	98.30	5,132,799	19.15
28	WI	106.00	5,536,201	19.15
29	GA	173.70	9,072,576	19.15
30	MI	185.80	10,120,860	18.36
31	IL	233.80	12,763,371	18.32
32	HI	22.30	1,275,194	17.49
33	SD	13.50	775,933	17.40
34	ME	22.80	1,321,505	17.25
35	NC	149.20	8,683,242	17.18
36	VA	126.40	7,567,465	16.70
37	NH	21.70	1,309,940	16.57
38	AZ	95.90	5,939,292	16.15
39	NJ	126.90	8,717,925	14.56
40	MD	81.00	5,600,388	14.46
41	FL	255.40	17,789,864	14.36
42	WA	83.40	6,287,759	13.26
43	MA	82.40	6,398,743	12.88
44	CT	43.50	3,510,297	12.39
45	OR	41.80	3,641,056	11.48
46	VT	6.90	623,050	11.07
47	NY	212.80	19,254,630	11.05
48	ID	15.40	1,429,096	10.78
49	CA	385.40	36,132,147	10.67
50	RI	10.80	1,076,189	10.04
51	DC	4.00	550,521	7.27
	Entire U.S.	5,872.70	296,410,404	19.81

Sources:

1. USPIRG's "The Carbon Boom: State and National Trends in Carbon Dioxide Emissions Since 1990"

2. Fact Monster's "Population by State"

Now there are some real numbers. Texas isn't great, ranking 11th, but compared to Wyoming they're quite efficient. Texas is above the national average, but only about one and half times worse. Poor California, previously libelled as being the 2nd worst state is actually the second best state on a per-person basis, running just about half the national average.

Update 2007-04-17: Two corrections: "desire" to "deserve" in "deserve this abuse", also corrected 10th to 2nd in discussing California. Thanks to Kathleen for pointing out these typos.