Table 2.

Comparison of estimated climatological impacts of various anesthetics relative to their clinical benefits over other anesthetics

Compound	Est. CO2 equivalents (kg/MAC-h)	Atmospheric lifetime (years)	Radiative forcing (W/m)	Radiative efficiency (W/m/ppb)	Benefits
CO2	–	Indefinite (100 +) [12, 76]	2.16 [12]	0.013665 [77]	–
Desflurane	72.78 [51]	12.3–14 [71, 78]	0.00017 [12]	0.469 [78]	• Fast induction [21] • Fast recovery in long procedures [21] and for obese patients [20] • Faster clearance [22] • Lower incidence of post-anesthetic agitation [34]
Sevoflurane	1.58 [51]	1.1–2 [71, 78]	0.00003 [12]	0.351 [78]	• Fast induction [21] • Fast recovery in long procedures [21] • Less airway irritation [40]
Isoflurane	2.98 [51]	3.2 [78]	0.00006 [12]	0.453 [78]	• Promotes bronchodilation in asthmatic patients [38, 39]
Halothane	N/A	3.6 [79]	0.000012 [53]	0.165 [78]	• Promotes bronchodilation in asthmatic patients [38, 39] • Low cost [80]
Enflurane	N/A	4.5 [71]	N/A	0.447 [78]	• Developed in the 1960s because it was easy to synthesize; however, rarely used now because of side effects [81]
Nitrous oxide	29.98 [51]	103–109 [51]	0.21 [12]	0.00303 [78]	• Subanesthetic concentrations produce a mild analgesic effect [82]

Enflurane largely disappeared from clinical practice in the 1990s and has been phased out from both human and veterinary medicine across high- and low-income countries by the 2020s. Halothane has fallen out of clinical use in most regions, with only limited use reported in parts of Africa as of 2024, and was removed from the World Health Organization's list of essential medicines in 2025 [83]. Enflurane and halothane are listed here for historical and comparative reference. MAC minimum alveolar concentration, N/A not applicable, ppb parts per billion, W/m², watts per square meter