Research press release


Nature Communications

Warming may compromise European ozone emissions reductions



今回、Audrey Fortems-Cheineyたちの研究グループは、地域的化学輸送モデルを用いて、気温が産業革命前と比べて摂氏2度または3度上昇することがヨーロッパにおけるオゾンの表面濃度に及ぼす影響をいろいろな緩和シナリオに基づいて調べた。温室効果ガス排出量が削減されないシナリオ(RCP8.5シナリオ)では、全球の気温が2040~2069年に摂氏3度上昇すると予測され、ある程度の緩和措置が実施されるシナリオ(RCP4.5シナリオ)では、全球の気温が2028~2057年に摂氏2度上昇すると予測されているが、この地域的化学輸送モデルを用いると、気温が摂氏3度上昇した場合にオゾン濃度が8%高くなることが明らかになった。この濃度差の原因について、Fortems-Cheineyたちは、RCP8.5シナリオでヨーロッパの境界付近のメタン濃度が高いためにオゾン濃度が上昇することを挙げている。


Warming of 3 degrees C, relative to pre-industrial conditions, reached by mid-century could compromise efforts to reduce ozone pollution in Europe, suggests a modelling study published in Nature Communications this week.

Ozone pollution remains an important environmental problem in Europe, but implementation of current air quality legislation is expected to result in considerable reductions of ozone precursor emissions. However, higher temperatures could also enhance ozone pollution.

Audrey Fortems-Cheiney and colleagues use a chemistry transport model to examine the effect of reaching either 2 degrees C or 3 degrees C of warming above pre-industrial levels under different mitigation scenarios on European ozone surface concentrations. The regional model shows that in a specific scenario with no mitigation of greenhouse gas emissions (known as RCP8.5), where 3 degrees C warming is reached sometime between 2040 and 2069, ozone levels are 8% higher compared to a scenario where moderate mitigation is implemented (RCP4.5) and only 2 degrees C warming is reached along the 2028-2057 period. The difference is attributed to higher methane concentrations at Europe’s boundaries in the RCP8.5 scenario, leading to an increase in ozone levels.

This specific modelling study suggests that ozone concentrations reached under a scenario with no mitigation and 3 degrees C warming by mid-century could outweigh reductions brought about by regulating ozone emissions. This finding highlights the need for implementation of regional emissions regulations as well as policies to reduce global methane concentrations. However the authors note that these projections relate to a specific region and climate scenario, and different emission or temperature trajectories may alter the predicted ozone increases.

doi: 10.1038/s41467-017-00075-9

「Nature 関連誌注目のハイライト」は、ネイチャー広報部門が報道関係者向けに作成したリリースを翻訳したものです。より正確かつ詳細な情報が必要な場合には、必ず原著論文をご覧ください。

メールマガジンリストの「Nature 関連誌今週のハイライト」にチェックをいれていただきますと、毎週最新のNature 関連誌のハイライトを皆様にお届けいたします。