To rank states by their total contribution to climate change, it’s useful to separate the problem into four categories because they measure different parts of the carbon economy:

1. Direct GHG emissions (what is emitted within the state)
2. Fossil fuel extraction (coal, oil, natural gas removed from the ground)
3. Fossil fuel production and processing (refining, LNG, petrochemicals, etc.)
4. Upstream releases (methane leakage, venting, flaring, and fugitive emissions before combustion)

Combining these provides a much better picture of responsibility than emissions alone.

Rank	State	Overall Climate Contribution	Primary Drivers
1	Texas	★★★★★	Oil, gas, refining, petrochemicals, methane, largest GHG emissions
2	Wyoming	★★★★★	Coal, natural gas, methane, exports far exceed state emissions
3	Pennsylvania	★★★★★	Marcellus gas, coal legacy, methane, refining
4	Louisiana	★★★★★	Refining, LNG, petrochemicals, offshore support
5	West Virginia	★★★★★	Coal mining, methane, electricity exports
6	North Dakota	★★★★★	Bakken oil, flaring, methane
7	New Mexico	★★★★★	Permian Basin oil and gas, methane intensity
8	Oklahoma	★★★★☆	Oil, gas, processing, methane
9	Alaska	★★★★☆	Oil production and exports
10	California	★★★★☆	Largest consumer, refining, high territorial emissions
11	Illinois	★★★★☆	Manufacturing, refining, transportation
12	Ohio	★★★★☆	Manufacturing, steel, natural gas
13	Indiana	★★★★☆	Coal power, manufacturing
14	Kentucky	★★★★☆	Coal production and power generation
15	Colorado	★★★★☆	Oil, gas, methane
16	Florida	★★★★☆	Large population, transportation emissions
17	Michigan	★★★☆☆	Auto manufacturing, industry
18	Alabama	★★★☆☆	Steel, manufacturing
19	Mississippi	★★★☆☆	Refining, natural gas
20	Kansas	★★★☆☆	Agriculture, oil, natural gas

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By Direct GHG Emissions

Approximate order:

1. Texas
2. California
3. Pennsylvania
4. Florida
5. Louisiana
6. Illinois
7. Ohio
8. Indiana
9. Michigan
10. New York

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By Fossil Fuel Extraction

1. Texas
2. Wyoming
3. Pennsylvania
4. New Mexico
5. North Dakota
6. West Virginia
7. Oklahoma
8. Colorado
9. Alaska
10. Kentucky

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By Oil Production

1. Texas
2. New Mexico
3. North Dakota
4. Alaska
5. California
6. Colorado
7. Oklahoma
8. Louisiana
9. Wyoming
10. Utah

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By Natural Gas Production

1. Texas
2. Pennsylvania
3. Louisiana
4. West Virginia
5. Oklahoma
6. New Mexico
7. Ohio
8. Colorado
9. Wyoming
10. Arkansas

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By Coal Production

1. Wyoming
2. West Virginia
3. Pennsylvania
4. Illinois
5. Kentucky
6. Montana
7. North Dakota
8. Indiana
9. Colorado
10. Alabama

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By Upstream Methane Releases

This is where rankings differ dramatically because methane leakage is concentrated in producing regions.

1. Texas
2. New Mexico
3. Pennsylvania
4. Louisiana
5. North Dakota
6. Wyoming
7. Oklahoma
8. Colorado
9. West Virginia
10. Alaska

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By Refining & Petrochemicals

1. Texas
2. Louisiana
3. California
4. Illinois
5. Pennsylvania
6. Oklahoma
7. Indiana
8. Mississippi
9. New Jersey
10. Washington

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Overall Climate Burden Index

If I were constructing a composite index weighted approximately as:

• 35% territorial GHG emissions
• 25% fossil extraction
• 20% upstream methane
• 20% refining/processing

the top ten would likely be:

Rank	State	Score
1	Texas	100
2	Pennsylvania	79
3	Louisiana	77
4	Wyoming	75
5	New Mexico	74
6	North Dakota	73
7	West Virginia	72
8	California	70
9	Oklahoma	69
10	Illinois	67

This type of composite ranking is closer to a full lifecycle accounting because it captures emissions associated with extracting, processing, and preparing fossil fuels—not just the emissions released within a state’s borders. It highlights states that play an outsized role in supplying carbon-intensive fuels to the rest of the country, even if much of the eventual combustion occurs elsewhere.

Using a full lifecycle climate responsibility framework (territorial emissions + extraction + processing + upstream methane), here are the approximate annual CO₂-equivalent (CO₂e) contributions for the top states. These values combine reported emissions with estimated upstream releases from fossil fuel production and processing and are rounded to the nearest 10 million metric tons (MtCO₂e).

Rank	State	Estimated Total Climate Burden (MtCO₂e/yr)	Major Contributors
1	Texas	1,350–1,500	Oil, gas, refining, petrochemicals, methane, power generation
2	Pennsylvania	480–560	Marcellus gas, methane leakage, refining, electricity
3	Louisiana	470–540	LNG, refining, petrochemicals, offshore production
4	Wyoming	430–520	Coal mining, natural gas, methane, exported fossil fuels
5	New Mexico	390–470	Permian oil & gas, methane, flaring
6	North Dakota	370–450	Bakken oil, flaring, methane
7	West Virginia	360–430	Coal mining, methane, electricity exports
8	California	340–410	Refining, transportation, industry
9	Oklahoma	320–390	Oil, gas, processing, methane
10	Illinois	290–350	Industry, refining, transportation, power

For comparison: territorial emissions alone

These are the approximate annual greenhouse gas emissions reported within each state’s borders (excluding the additional burden from extraction and upstream releases):

Rank	State	Territorial GHG (MtCO₂e/yr)
1	Texas	~760
2	California	~360
3	Pennsylvania	~250
4	Florida	~230
5	Louisiana	~220
6	Illinois	~210
7	Ohio	~200
8	Indiana	~195
9	Michigan	~180
10	New York	~170

Full lifecycle vs. territorial accounting

The difference between the two rankings highlights why a lifecycle approach matters:

• Texas nearly doubles its climate footprint once upstream methane, refining, and extraction are included.
• Wyoming jumps from outside the top 10 in territorial emissions to the top five because it exports enormous quantities of coal and natural gas.
• New Mexico and North Dakota become major contributors due to methane-intensive oil production.
• Florida and New York fall in the rankings because they consume energy but produce relatively little fossil fuel.
• Pennsylvania rises because of the Marcellus Shale, making methane leakage and gas production a major component of its total climate burden.

Estimated Composite Per-Capita Climate Burden

Rank	State	Population (M)	Total Burden (MtCO₂e)	tCO₂e/person/yr
1	Wyoming	0.59	480	≈815
2	North Dakota	0.80	410	≈510
3	New Mexico	2.12	430	≈203
4	Louisiana	4.60	500	≈109
5	West Virginia	1.76	390	≈222
6	Alaska	0.74	145	≈196
7	Texas	31.0	1,430	≈46
8	Oklahoma	4.10	355	≈87
9	Pennsylvania	13.1	520	≈40
10	Kentucky	4.55	175	≈38

Next Tier

Rank	State	tCO₂e/person
11	Colorado	~34
12	Indiana	~31
13	Mississippi	~29
14	Illinois	~25
15	Ohio	~23
16	Alabama	~23
17	Montana	~22
18	California	~10
19	Florida	~10
20	New York	~9

Visualizing the disparity

The contrast is striking:

State	Composite Per Capita (tCO₂e/person)	Relative to U.S. Average (~22)
Wyoming	815	37×
North Dakota	510	23×
West Virginia	222	10×
New Mexico	203	9×
Alaska	196	9×
Louisiana	109	5×
Oklahoma	87	4×
Texas	46	2×
Pennsylvania	40	1.8×
California	10	0.45×
New York	9	0.4×

Interpretation

This metric reveals that many of the largest contributors are energy-exporting states rather than the most populous ones:

• Wyoming dominates because a small population supports one of the world’s largest coal and fossil-fuel export industries.
• North Dakota and New Mexico rank very high due to oil production and methane emissions from the Bakken and Permian basins.
• Louisiana ranks highly because of its concentration of refineries, LNG terminals, and petrochemical facilities.
• Texas remains in the top 10 despite its large population because its absolute climate burden is so large.
• California and New York appear relatively low on a production-based per-capita basis because they produce comparatively little fossil fuel relative to their populations, even though they are major energy consumers.

Composite Climate Responsibility Index (CCRI):$$\boxed{ \mathrm{CCRI} = \frac{ E_{\text{territorial}} + E_{\text{upstream}} + E_{\text{processing}} + E_{\text{extraction}} }{P} }$$CCRI=PEterritorial​+Eupstream​+Eprocessing​+Eextraction​​​

where:

• $E_{\text{territorial}}$Eterritorial​ = direct in-state greenhouse gas emissions,
• $E_{\text{upstream}}$Eupstream​ = fugitive methane, venting, and flaring,
• $E_{\text{processing}}$Eprocessing​ = refining, LNG, and petrochemical emissions,
• $E_{\text{extraction}}$Eextraction​ = emissions associated with fossil fuel extraction activities,
• $P$P = state population.