page_title: James Lovelock
section_title: CFCs
hierarchical_section_title: James Lovelock / Career / CFCs
caption_attribution_description: English: Time series of atmospheric concentrations of CFC-11 from 1931 to 2003. Mixing ratio concentrations are shown for the northern and southern hemispheres, and are expressed as parts per trillion. The dotted line at 1989 incidates the time at which the Montreal Protocol on Substances That Deplete the Ozone Layer came into force. The data are plotted here using MATLAB. The published source of data for the figure is: Walker, S. J., R. F. Weiss &amp; P. K. Salameh (2000) Reconstructed histories of the annual mean atmospheric mole fractions for the halocarbons CFC-11, CFC-12, CFC-113 and carbon tetrachloride. Journal of Geophysical Research 105, 14285—14296. The data (including error estimates and updates) are available online from the atmospheric halocarbon page at University of California, San Diego.
context_page_description: James Ephraim Lovelock, CH CBE FRS is an English independent scientist, environmentalist, and futurist. He is best known for proposing the Gaia hypothesis, which postulates that the Earth functions as a self-regulating system.
  With a PhD in medicine, Lovelock began his career performing cryopreservation experiments on rodents, including successfully thawing frozen specimens. His methods were influential in the theories of cryonics. He invented the electron capture detector, and using it, became the first to detect the widespread presence of CFCs in the atmosphere. While designing scientific instruments for NASA, he developed the Gaia hypothesis.
  In the 2000s, he proposed a method of climate engineering to restore carbon dioxide-consuming algae. He has been an outspoken member of Environmentalists for Nuclear, asserting that fossil fuel interests have been behind opposition to nuclear energy, citing the effects of carbon dioxide as being more harmful to the environment, and warning of global warming due to the greenhouse effect. He has written several environmental science books based upon the Gaia hypothesis since the late 1970s.
context_section_description: After the development of his electron capture detector, in the late 1960s, Lovelock was the first to detect the widespread presence of CFCs in the atmosphere. He found a concentration of 60 parts per trillion of CFC-11 over Ireland and, in a partially self-funded research expedition in 1972, went on to measure the concentration of CFC-11 from the northern hemisphere to the Antarctic aboard the research vessel RRS Shackleton. He found the gas in each of the 50 air samples that he collected but, not realising that the breakdown of CFCs in the stratosphere would release chlorine that posed a threat to the ozone layer, concluded that the level of CFCs constituted "no conceivable hazard". He has since stated that he meant "no conceivable toxic hazard".
  However, the experiment did provide the first useful data on the ubiquitous presence of CFCs in the atmosphere. The damage caused to the ozone layer by the photolysis of CFCs was later discovered by Sherwood Rowland and Mario Molina. After hearing a lecture on the subject of Lovelock's results, they embarked on research that resulted in the first published paper that suggested a link between stratospheric CFCs and ozone depletion in 1974 (for which Sherwood and Molina later shared the 1995 Nobel Prize in Chemistry with Paul Crutzen).
caption: Reconstructed time-series of atmospheric concentrations of CFC-11[27]
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