evidence: In dialogues about ocean issues, the effects of greenhouse gases, such as ground-level ozone and carbon dioxide, haven’t received nearly as much attention as plastic, largely because they aren’t visible. But oxygen is as essential for the ocean as it is on land. And while it can vary at different depths, rising sea temperatures have caused deep ocean areas already low in oxygen, to deoxygenate further, changing habitats for underwater life. A report published recently by the World Meteorological Organization revealed that more than 90 per cent of the energy trapped by greenhouse gases goes into the oceans. Last year saw new highs of ocean temperature in the top 700 metres and 2,000 metres of water, surpassing the previous record set in 2017. [...] Greenhouse gases are the main source of air pollution and include carbon dioxide, methane, nitrous oxide and sulphur hexafluoride. While some gases are produced through natural processes like animal and plant respiration, human activity such as fossil fuel burning, livestock rearing and vehicle emissions have increased their quantity.