Jack Harris recalls two remarkable Americans

Either side of the longest day of the year, two outstanding American scientists departed this life - Jack Kilby on June 20th and Charles Keeling two days later.

The following day, June 23rd, Kilby’s obituary appeared in the Times and Keeling’s in the Guardian. As I take both papers I naturally read both obituaries, and I was struck by the important impact each had, or should have had, on the world community.

Their differences are more interesting than their similarities.  To start with, Kilby was a Nobel Laureate whereas Keeling wasn’t, but should have been.  Kilby’s discovery had an enormous impact on contemporary life whereas Keeling’s hasn’t, though it should have.  Kilby’s discoveries indicate a comfortable and prosperous future for mankind, whereas Keeling’s findings predict change and insecurity.

Kilby’s circuit

On September 12th 1958 (the obituary was strangely specific) Kilby invented the integrated circuit, commonly known as the microchip, which replaced the transistor, which in 1947 had replaced the radio valve.  The integrated circuit brought transistors down to atomic dimensions and permitted huge volumes of information to be transferred in a very short time in micro-sized components.

Computers became portable and universal, mobile phones ubiquitous and information technology was born.  The microchip is transforming our lives.  Microchips also use little energy and in later life Kilby became interested in developing silicon chips to convert solar energy into electricity – so he has some green credentials.

Keeling’s CO2 measurements

Keeling first took an interest in the chemistry of the atmosphere as a post-doctoral researcher at the California Institute of Technology in the mid 1950s. He became frustrated that measurements of carbon dioxide levels showed no consistent value, but were affected by local factors and poor instrumentation.

Meanwhile, at the Scripps Institute of Oceanography, Roger Revelle demonstrated that the oceans were incapable of absorbing all the human-generated carbon dioxide, so this impurity might accumulate in the atmosphere.  During 1957-8, the International Geophysical Year, Revelle recruited Keeling and charged him to carry out accurate measurements of atmospheric carbon dioxide levels.

Revelle could not have made a better choice.  Keeling set about making more accurate instruments and from measurements in the Antarctic soon began demonstrating that global carbon dioxide levels were indeed rising.  However, his most famous achievement resulted from data obtained from the carbon dioxide measuring station he set up on top of the volcanic peak Mauna Loa in Hawaii.

With remarkable persistence, very accurate measurements of atmospheric carbon dioxide levels have been made from 1958 to the present time – approaching half a century.  Each year there is a variation on a yearly basis as photosynthesis in summer is replaced by foliage decay in winter.  The striking result though is a steady increase in carbon dioxide level with the passage of years, from 315 ppm in 1958 to about 375 ppm today.  His plot of carbon dioxide content versus time is now known universally as ‘Keeling’s Curve’ and it has become perhaps the most famous curve in science, and the most menacing.

Near misses

The Guardian obituary draws attention to the fact that, earlier this year, Keeling was the only American atmospheric scientist brave enough to speculate on the significance of the fact that, for the first time since records began, the carbon dioxide content of the atmosphere had risen by two parts per million for two years running.  The silence of Keeling’s colleagues has been attributed to President Bush’s determination to rubbish any scientific evidence which supports the occurrence of anthropogenic warming.

On the other hand, President Bush did award Keeling the 2002 National Medal of Science – the highest American award for a lifetime of scientific achievement.  Perhaps no one explained to the President what Keeling’s achievements actually were!

In 1966, when he was an undergraduate at Harvard, Al Gore was so inspired by a lecture by Roger Revelle on ‘The Future of the Earth’ that he became an environmentalist.  This may explain why, as Vice President Gore, he enthusiastically signed, on behalf of the USA, the 1997 Kyoto Protocol on Climate Change.  This was later rescinded by President Bush.

It is a sobering thought that, but for a few votes lost in Florida, or the intervention of the green candidate, there would have been no war with Iraq and America might have ratified the Kyoto Protocol.

Jack Harris is vice-chairman of British Pugwash.