31 March 1908		29 May 2001
	Self-portrait, aged 18

My father, who would have been 100 years old this year, had three concerns about the life support systems of the planet, which he talked about over fifty years ago:

• Having seen large-scale logging in West Africa when he served in the Navy during World War II, he was worried that the tropical rainforests of the world might be progressively destroyed, and said how valuable they were for their enormous variety of species and how they could not be replaced, and every patch was different and was vital.

• When jet airliners became a commercial possibility (the first commercial jet airliners to come into operation was BOAC’s DH Comet in 1954), he was afraid that planes flying through the ‘heavyside layer’ of the upper atmosphere – what we now call the ‘ozone layer’ – would result in the protective covering which shields life on earth from high energy radiation being broken up. His fear of the consequences was worse than people getting skin cancers, it was that widespread genetic mutations affecting all life on Earth could result.

• My father’s third main concern was that pollution from the land, such as untreated sewage discharged into the sea, could kill off the micro-organisms: phytoplankton, blue-green algae or cyanobacteria, living in the ocean waters over the continental shelves, which he said produce most of the oxygen in the atmosphere – he said it was these populations which were ‘the lungs of the Earth’, not forests, which were important in other ways, but not so much for that. These micro-organisms are also, he explained, involved in the crucial role of the ocean as a carbon sink. These tiny plants are at the top of the ocean food chain: eaten by fauna of all shapes and sizes, the carbon in the organic chemicals of their cells (products of photosynthesis) end up in shellfish, and when the shellfish die their bodies sink as a litter of carbonates to the ocean floor, which in geological timescales becomes limestone at the top of Everest etc. Without that process, the capacity of the oceans as a carbon sink is limited to how much carbon can be dissolved in the water. My father may have been wrong about the eutrofication route to the disruption of that process (it is now thought to be acidification from dissolved carbon), but I fear he will be proven right about the consequences.

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