EigoPro 1級 読解 — The Other Carbon Problem: Why Acidifying Seas Defy Our Gaze

When we lament the carbon we have loosed upon the atmosphere, we fixate almost exclusively on heat. Yet roughly a quarter of anthropogenic carbon dioxide never lingers in the air; it dissolves into the ocean, where it reacts with seawater to form carbonic acid. The result is a slow, pervasive shift in marine chemistry that scientists call ocean acidification—aptly dubbed climate change's evil twin, or simply the other carbon problem. The mechanism is deceptively quiet. As dissolved CO2 lowers the water's pH, it depletes the carbonate ions that countless organisms require to build shells and skeletons. Corals, oysters, sea urchins, and the minuscule pteropods at the base of polar food webs must now expend more energy to fabricate the structures that once formed almost effortlessly. In waters acidic enough, existing shells begin to dissolve outright, and larvae perish before they can ever mature. The corrosion is chemical, not thermal, and it advances inexorably regardless of whether a given patch of sea happens to feel pleasantly warm to a swimmer's hand. Herein lies the insidious difficulty: acidification is far harder to perceive than warming. A heatwave bleaches a reef before our eyes and registers on any thermometer; a tenth of a point on the pH scale betrays nothing to ordinary observation, even as it represents a thirty-percent surge in acidity. The damage accrues invisibly, beneath the surface, on timescales that elude casual notice and outpace political attention. This imperceptibility is precisely why the threat is so easily marginalised. We legislate against what we can see and dramatise; we neglect, almost reflexively, what unfolds silently in solution and leaves no scorched landscape behind. To treat acidification as a mere footnote to warming, however, is to misread the chemistry and to mistake the symptom for the whole disease. It is a distinct insult inflicted by the same culprit, and unless we curb emissions at their source, no amount of attention lavished on temperature alone will ever suffice to spare the chemical foundations of marine life.

5問合格 60%以上普通

新規登録 または ログイン が必要です

この単元の問題を3問、解説つきで公開しています

1級 · 読解 · 全5問

問 1

Which statement best captures the central argument of the passage?

  • The dissolving of shells is a natural process that marine organisms have always managed without expending extra energy.
  • Rising ocean temperatures pose a greater immediate threat to marine life than changes in seawater chemistry.
  • Ocean acidification is a distinct, chemically driven consequence of carbon emissions whose invisibility causes it to be dangerously overlooked.
  • Acidification can be reversed simply by directing more political and legislative attention toward warming oceans.
Phrase

the other carbon problem

1級読解主旨把握論旨
⚡ひとことで

酸性化は温暖化とは別個の化学的脅威で、見えにくいがゆえに軽視されている、というのが論旨。

選択肢の解説Choice Analysis

「Ocean acidification is a distinct, chemically driven consequence of carbon emissions whose invisibility causes it to be dangerously overlooked.」

正解

筆者は酸性化を「climate change's evil twin, or simply the other carbon problem」と呼び、熱ではなく化学反応による被害だと強調する。さらに「acidification is far harder to perceive than warming」と述べ、その不可視性こそが軽視される理由だと論じる。よってこの選択肢が主旨を正確に捉えている。

  • 「Rising ocean temperatures pose a greater immediate threat to marine life than changes in seawater chemistry.」

    = 海水温の上昇のほうが化学変化より差し迫った脅威だとする ━ 筆者は両者を「distinct insult inflicted by the same culprit」と並置し、温暖化を上位に置いていない。むしろ酸性化が footnote 扱いされる誤りを批判している。。

  • 「The dissolving of shells is a natural process that marine organisms have always managed without expending any extra energy.」

    = 殻の溶解は生物が常に対処してきた自然な過程だとする ━ 本文は「must now expend more energy」「shells begin to dissolve outright」と、新たに生じる負荷・損傷として描いており、無害な自然過程ではない。。

  • 「Acidification can be reversed simply by directing more political and legislative attention toward warming oceans.」

    = 温暖化に注目を集めれば酸性化は容易に逆転できるとする ━ 筆者は注目だけでは不十分とし「unless we curb emissions at their source」と排出源の抑制を解決条件に挙げている。注目の転換では解決しない。。

▦Collocation
パターン意味例
the other carbon problemもう一つの炭素問題Acidification is often called the other carbon problem.
a quarter of anthropogenic CO2人為起源CO2の約4分の1About a quarter of anthropogenic CO2 is absorbed by the sea.
dissolve into the ocean海洋に溶け込むMuch of the gas dissolves into the ocean each year.
a slow, pervasive shift緩慢で広範な変化Chemistry undergoes a slow, pervasive shift.
climate change's evil twin気候変動の邪悪な双子Some scientists name it climate change's evil twin.
❝例文

  • The essay's thesis is that an invisible danger is the most easily ignored.

    この論考の主張は、見えない危険ほど無視されやすいというものだ。

  • Grasping the central argument requires reading past the obvious headline.

    中心的な論旨をつかむには、目立つ見出しの先を読む必要がある。

  • She summarised the author's stance in a single, precise sentence.

    彼女は筆者の立場を一文で正確に要約した。

  • The passage frames acidification as a problem in its own right.

    本文は酸性化をそれ自体独立した問題として位置づける。

💡Tip · 覚えるコツ

主旨問題は、本文が繰り返し強調する語句(ここでは other carbon problem / harder to perceive)を手がかりにすると外しにくい。

問 2

According to the passage, what specifically happens to carbonate ions as dissolved CO2 lowers the water's pH?

  • They are depleted, leaving fewer of them for organisms to build shells and skeletons.
  • They combine with calcium to form a protective layer that shields reefs from warming.
  • They multiply rapidly, allowing organisms to construct shells with far less effort than before.
  • They evaporate from the surface waters and return to the atmosphere as carbon dioxide.
Phrase

it depletes the carbonate ions

1級読解詳細把握
⚡ひとことで

pHが下がると炭酸イオンが減少し、殻や骨格の形成が難しくなる。

選択肢の解説Choice Analysis

「They are depleted, leaving fewer of them for organisms to build shells and skeletons.」

正解

本文は「As dissolved CO2 lowers the water's pH, it depletes the carbonate ions that countless organisms require to build shells and skeletons」と明記する。つまり炭酸イオンは増えるのではなく減る。その結果、生物はより多くのエネルギーを費やさねばならない。

  • 「They multiply rapidly, allowing organisms to construct shells with far less effort than before.」

    = 炭酸イオンが急増し殻形成が容易になるとする ━ 本文は deplete(枯渇させる)であって増加ではない。生物は「expend more energy」と、むしろ負担が増す。。

  • 「They combine with calcium to form a protective layer that shields reefs from warming.」

    = カルシウムと結合して温暖化からサンゴを守る層を作るとする ━ そのような保護層の記述はなく、本文の論点は熱ではなく化学的腐食である。。

  • 「They evaporate from the surface waters and return to the atmosphere as carbon dioxide.」

    = 表層から蒸発しCO2として大気に戻るとする ━ 炭酸イオンが蒸発するという記述はない。CO2はむしろ海に溶け込むと述べられている。。

▦Collocation
パターン意味例
lower the pHpHを下げるDissolved gas can lower the pH of seawater.
deplete the carbonate ions炭酸イオンを枯渇させるAcidification depletes the carbonate ions in the water.
build shells and skeletons殻や骨格を作るMany organisms build shells and skeletons from carbonate.
expend more energyより多くのエネルギーを費やすCorals must expend more energy to grow.
at the base of food webs食物網の底辺でPteropods sit at the base of polar food webs.
❝例文

  • The reaction depletes a resource the larvae cannot do without.

    その反応は幼生に不可欠な資源を枯渇させる。

  • Fewer carbonate ions mean weaker, thinner shells.

    炭酸イオンが減れば殻は薄く脆くなる。

  • Builders of calcium structures are hit first.

    カルシウム構造を作る生物が真っ先に打撃を受ける。

  • The chemistry quietly raises the cost of survival.

    その化学反応は生存の代償を静かに引き上げる。

💡Tip · 覚えるコツ

detail 問題は本文の動詞(deplete=枯渇)を正確に追うこと。反対方向(増加・保護)の選択肢は典型的なひっかけ。

問 3

Why does the passage say acidification is harder to perceive than warming?

  • A small pH change reveals nothing to ordinary observation even though it marks a large rise in acidity, and the damage accrues invisibly underwater.
  • Thermometers cannot detect heatwaves, whereas pH meters give instant, dramatic readings.
  • Acidification only affects deep-sea organisms that no instrument is capable of measuring.
  • Warming and acidification occur in entirely separate oceans, so the two are never observed together.
Phrase

betrays nothing to ordinary observation

1級読解詳細把握
⚡ひとことで

わずかなpH変化は普通の観察では分からないが、実は酸性度が大きく上がっている。

選択肢の解説Choice Analysis

「A small pH change reveals nothing to ordinary observation even though it marks a large rise in acidity, and the damage accrues invisibly underwater.」

正解

本文は熱波は目に見え温度計に表れるのに対し、「a tenth of a point on the pH scale betrays nothing to ordinary observation, even as it represents a thirty-percent surge in acidity」と対比する。被害は「accrues invisibly, beneath the surface」と蓄積するため知覚しにくい。

  • 「Acidification only affects deep-sea organisms that no instrument is capable of measuring.」

    = 深海生物だけが影響を受け測定できないからとする ━ 本文はサンゴ・カキ・ウニなど表層・浅海の生物も挙げ、深海限定ではない。pHは測定可能だが日常観察で気づかないという論点。。

  • 「Warming and acidification occur in entirely separate oceans, so the two are never actually observed together anywhere in the world.」

    = 温暖化と酸性化は全く別の海で起こり同時に観察されないとする ━ 本文は同じ海で「regardless of whether a given patch of sea happens to feel pleasantly warm」と両者が重なり得ることを示している。。

  • 「Thermometers cannot detect heatwaves, whereas pH meters give instant, dramatic readings.」

    = 温度計は熱波を検知できず、pH計は劇的な値を出すとする ━ 本文は逆で、熱波は「registers on any thermometer」、pHの変化こそ「betrays nothing」と述べている。。

▦Collocation
パターン意味例
harder to perceive知覚しにくいSlow change is harder to perceive than a sudden one.
betray nothing to observation観察に何も示さないA subtle shift betrays nothing to casual observation.
a surge in acidity酸性度の急増A small pH drop means a surge in acidity.
accrue invisibly目に見えず蓄積するThe harm accrues invisibly over decades.
elude casual notice何気ない注意を逃れるGradual decline tends to elude casual notice.
❝例文

  • The change is real on the instruments yet absent to the naked eye.

    その変化は計器上は実在するが肉眼には映らない。

  • A logarithmic scale hides how large a small step truly is.

    対数尺度は小さな一歩の大きさを覆い隠す。

  • Slow harm rarely triggers alarm in time.

    緩慢な害は手遅れになるまで警報を鳴らさない。

  • What escapes the senses easily escapes the agenda.

    感覚を逃れるものは議題からも容易にこぼれ落ちる。

💡Tip · 覚えるコツ

why 問題は本文の対比構造(熱波=可視 / pH=不可視)を押さえると正解選択肢の根拠が明快になる。

残り2問は、解いて確かめられます

全5問すべてに、この形式の解説が付いています。 間違えた問題は記録され、あとから復習できます。

無料で登録して続きを解く

インストール不要・カード登録なし・いま全機能無料

この単元の講義を見る1級の単元一覧1級の用語集