気づかない５つの環境の衰え

イギリスのガーディアン紙(2021/10/14)が、私の忘れていた５つの視点を整理してくれました。来月始まる気候変動に関するCOP26会議のタイミングで、振り返ります。どれも バイオ・ダイバーシティに関わる深刻な課題です。

１　1970 年以降、陸地の1/3と淡水資源(川や湖）の3/4が畑や酪農に使われ、野生動物が住めなくなった

２　動植物や天然資源が過度に利用されバイオ・ダイバーシティが減少した

３　気候変動でバイオ・ダイバーシティが減少した

４　陸上の農薬や肥料由来の窒素やリンの汚染は海洋のエコシステムを壊し、海洋のプラスチック汚染はこの40年間で10倍になった

５　外来種の侵入により在来種が絶滅した

私は特に4番と5番が印象深いです。4番に書いてある農業由来の海洋汚染。これに加えて工業排水や家庭の合成界面活性剤による海洋汚染は、きちんと測定評価されているのでしょうか。大変疑問に思います。

5番に書いてある外来種による在来種の駆逐の問題は、別の記事でイギリス森林の在来種の樹木の枯死の記事を読んだところでした。

ガーディアン紙の記事。

https://www.theguardian.com/environment/2021/oct/14/five-biggest-threats-natural-world-how-we-can-stop-them-aoe?CMP=Share_AndroidApp_Other

以下はイギリス・ガーディアン紙から引用。前掲の記事の要約になっています。

1. For terrestrial and freshwater ecosystems, land-use change has had the largest relative negative impact on nature since 1970. More than a third of the world’s land surface and nearly 75% of freshwater resources are now devoted to crop or livestock production. Alongside a doubling of urban area since 1992, things such as wetlands, scrubland and woodlands – which wildlife relies on – are ironed out from the landscape. 2. The direct exploitation of organisms and non-living materials, including logging, hunting and fishing and the extraction of soils and water are all negatively affecting ecosystems. In marine environments, overfishing is considered to be the most serious driver of biodiversity loss. One quarter of the world’s commercial fisheries are overexploited, according to a 2005 Millennium Ecosystem Assessment. 3. The climate crisis is dismantling ecosystems at every level. Extreme weather events such as tropical storms and flooding are destroying habitats. Warmer temperatures are also changing the timing of natural events – such as the availability of insects and when birds hatch their eggs in spring. The distribution of species and their range is also changing. 4. Many types of pollution are increasing. In marine environments, pollution from agricultural runoff (mainly nitrogen and phosphorus) do huge damage to ecosystems. Agricultural runoff causes toxic algal blooms and even "dead zones" in the worst affected areas. Marine plastic pollution has increased tenfold since 1980, affecting at least 267 species. 5. Since the 17th century, invasive species have contributed to 40% of all known animal extinctions. Nearly one fifth of the Earth’s surface is at risk of plant and animal invasions. Invasive species change the composition of ecosystems by outcompeting native species.