温室効果ガス濃度、２０１８年は観測史上最高に　世界気象機関

【ジュネーブＡＦＰ＝時事】国連の世界気象機関（WMO）は25日、気候変動の主な原因である温室効果ガスの大気中濃度が、昨年、観測史上最も高い数値を記録したと発表し、「将来の人類の幸福」を守るための行動を呼び掛けた。（写真は資料写真）
　ＷＭＯのペッテリ・ターラス事務局長は、「地球温暖化対策の国際的枠組みであるパリ協定の下でのあらゆる取り組みにもかかわらず、大気中の温室効果ガス濃度の上昇は減速する兆しがなく、まして低下など全く見られない」と述べた。
　ＷＭＯの温室効果ガス年報によると、２０１８年の二酸化炭素の大気中濃度は４０７．８ｐｐｍで、２０１７年の４０５．５ｐｐｍから上昇した。上昇幅は、過去１０年の年間上昇幅の平均をわずかながらも上回った。二酸化炭素は地球温暖化の要因の約３分の２を占める。
　ＷＭＯによると、二酸化炭素に次ぐ主な温室効果ガスであるメタンと亜酸化窒素の大気中濃度も昨年、観測史上最高を記録した。
　報告書でＷＭＯは「この継続している長期的な傾向は、将来の世代が気温の上昇や極端な気候、水不足、海面上昇、陸・海上の生態系の破壊といった、深刻な気候変動の影響を受けることになることを意味する」と述べた。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2019/11/26-10:33）

Greenhouse gases levels in the atmosphere, the main driver of climate change, hit a record high last year, the UN said Monday, calling for action to safeguard the future welfare of mankind.
There is no sign of a slowdown, let alone a decline, in greenhouse gas concentration in the atmosphere despite all the commitments under the Paris Agreement on Climate Change, the head of the World Meteorological Organization (WMO) Petteri Taalas said in a statement.
The WMO's main annual Greenhouse Gas Bulletin listed the atmospheric concentration of CO2 in 2018 at 407.8 parts per million, up from 405.5 parts per million (ppm) in 2017.
That increase was just above the annual average increase over the past decade.
CO2 is responsible for roughly two-thirds of Earth's warming.
The second most prevalent greenhouse gas in the atmosphere is methane -- emitted in part from cattle and fermentation from rice paddies -- which is responsible for 17 percent of warming, according to WMO.
Nitrous oxide, the third major greenhouse which is gas caused largely by agricultural fertilisers, has caused about six percent of warming on Earth, the UN agency said.
Atmospheric concentration levels of both methane and nitrous oxide both hit record highs last year, the UN said.
This continuing long-term trend means that future generations will be confronted with increasingly severe impacts of climate change, including rising temperatures, more extreme weather, water stress, sea level rise and disruption to marine and land ecosystems, WMO said.
- 'More hopeful'? -
Emissions are the main factor that determine the amount of greenhouse gas levels but concentration rates are a measure of what remains after a series of complex interactions between atmosphere, biosphere, lithosphere, cryosphere and the oceans.
Roughly 25 percent of all emissions are currently absorbed by the oceans and biosphere -- a term that accounts for all ecosystems on Earth.
The lithosphere is the solid, outer part of the Earth while the cyrosphere covers that part of the world covered by frozen water.
The UN's Intergovernmental Panel on Climate Change (IPCC) has said that in order to keep warming below 1.5 degrees Celsius, net CO2 emissions must be at net zero, meaning the amount being pumped into the atmosphere must equal the amount being removed, either though natural absorbtion or technological innovation.
While Taalas made clear that the world was not on track to meet UN targets, he did highlight some reasons for cautious optimism.
The visibility of these issues is the highest (it has) ever been, he told reporters in Geneva, noting that the private sector was increasingly investing in green technology.
Even in the United States, where President Donald Trump's administration this month began the process of formally withdrawing from the Paris agreement, plenty of positive things are happening, Taalas said.
While Washington may have renounced its Paris agreement commitments, we have plenty of states and cities who are proceeding in the right direction, he added.
Personally, I am more hopeful than I used to be 10 years ago but of course we have to speed up the process, Taalas said.