The concentration of atmospheric carbon dioxide at Mauna Loa Observatory, Hawaii is reported for eight years (1964–1971) of a long term program to document the effects of the combustion of coal, petroleum, and natural gas on the distribution of CO2 in the atmosphere. The new data, when combined with earlier data, indicate that the annual average CO2 concentration rose 3.4% between 1959 and 1971. The rate of rise, however, has not been steady. In the mid‐1960's it declined. Recently it has accelerated. Similar changes in rate have been observed at the South Pole and are evidently a global phenomenon.

The concentration of atmospheric carbon dioxide at Mauna Loa Observatory, Hawaii is reported for eight years (1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)) of a long term program to document the effects of the combustion of coal, petroleum, and natural gas on the distribution of CO, in the atmosphere. The new data, when combined with earlier data, indicate that the annual average CO, concentration rose 3.4 ' % between 1959 and 1971. The rate of rise, however, has not been steady. In the mid-1960's it declined. Recently i t has accelerated. Similar changes in rate have been observed at the South Pole and are evidently a global phenomenon.

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Duplicate measurements of 749 discrete samples of air collected at the South Pole indicate that the seasonally adjusted concentration of atmospheric carbon dioxide in the polar southern hemisphere rose 3.7 % between 1957 and 1971. The rise, mostly attributable to the burning of fossil fuels, has not been steady. In the mid-l960's, possibly as a result of wide-spread cooling of surface ocean water, it slackened for several years; recently it has accelerated. Similar changes in rate have also been observed at Mauna Loa Observatory, Hawaii, in the northern hemisphere and are evidently a global phenomenon.

When completed, the DARHT-II linear induction accelerator (LIA) will produce a 2-kA, 17-MeV electron beam in a 1600-ns flat-top pulse. In initial tests, DARHT-II accelerated beams with current pulse lengths from 500 to 1200 ns full-width at half-maximum (FWHM) with more than 1.2-kA, 12.5-MeV peak current and energy. Experiments have now been done with a 1600-ns pulse length. These pulse lengths are all significantly longer than any other multimegaelectronvolt LIA, and they define a novel regime for high-current beam dynamics, especially with regard to beam stability. Although the initial tests demonstrated insignificant beam-breakup instability (BBU), the pulse length was too short to determine whether ion-hose instability would be present toward the end of a long, 1600-ns pulse. The 1600-ns pulse experiments reported here resolved these issues for the long-pulse DARHT-II LIA.