飛行経路の最適化で地球温暖化を緩和（Smarter flight decisions can cool the planet, UC Irvine study shows）

2025-07-02 カリフォルニア大学アーバイン校（UCI）

＜関連情報＞

• https://news.uci.edu/2025/07/02/smarter-flight-decisions-can-cool-the-planet-uc-irvine-study-shows/
• https://www.nature.com/articles/s41586-025-09198-2

航空機が気候に与える影響におけるトレードオフは、CO2以外の緩和策を支持する Trade-offs in aviation impacts on climate favour non-CO2 mitigation

Michael J. Prather,Andrew Gettelman & Joyce E. Penne
Nature  Published:02 July 2025
DOI:https://doi.org/10.1038/s41586-025-09198-2

Abstract

Climate assessments of civil aviation^1,2 have consistently quantified the dominant climate-forcing components: (1) CO₂ emissions, (2) NO_x (NO + NO₂) emissions and (3) persistent contrails. All three components exert a positive radiative forcing (RF) and lead to climate warming of similar magnitudes. The aviation community is actively seeking to reduce its climate footprint through advanced engine technologies, more sustainable aviation fuel and optimal routing plans^{3,4,5,6,7,8,9,10,11,12}. These approaches usually involve a trade-off of CO₂ against NO_x or contrails (non-CO₂), such as burning 1% more fuel to decrease contrail RF by 4%. Here, we show that a climate-trade-off risk curve derived from uncertainties in the RF components^{2,13,14,15,16} can give the probability that a specified trade-off ratio will produce a climate benefit. For each component, we calculate the integrated effective RF resulting from 1 year of flights: global warming per activity (GWA). The complementary cumulative probability distribution of the GWA(non-CO₂) to GWA(CO₂) ratio results in a climate-trade-off risk curve giving the likelihood of a positive climate outcome as a function of the trade-off-CO₂ to trade-off-non-CO₂ ratio, because the product, GWA × trade-off, should be the same for both. We find a likely (67%) chance of climate mitigation on a 100-year time horizon for the above suggested ratio of 1:4, favouring proposed non-CO₂ mitigation efforts^{3,4,5,6,7,8,9,10,11,12} with ratios smaller than this.