Carbon dioxide drawdown

Thermoformable foamed PP sheet that processes with the same drawdown, sag and cycle times as PS has been manufactured by Omam using new PP blends and Safoam carbon dioxide blowing agents from Reedy International. Oman has already produced monolayer PP sheet with a 40% density reduction and three layer sheet with a 50% density reduction. The trials have been carried out using blends of conventional PP and a new high melt strength PP grade developed by Montell. The Omam line used to produce the foamed PP sheet is conventional apart from... 

Figure 9 A transect through the IronEx II patch. The x-axis shows GMT as the ship steams from east to west through the center of the patch. Simultaneously plotted are the iron-induced production of chlorophyll, the drawdown of carbon dioxide, and the uptake of nitrate in this bloom.

So, where did all the carbon go What mechanisms caused the drawdown of carbon dioxide and the removal of a substantial volume of carbon from the actively circulating part of its biogeochemical cycle These questions have not yet been satisfactorily explained but it is likely that life forms increased their uptake of atmospheric carbon dioxide substantially. Possibly, algae in the oceans were responsible. Alternatively or additionally, increased productivity by tropical and semitropical ecosystems may have been stimulated when they increased in extent as land emerged from the continental shelf sea-levels due to ice accumulation and sea-level fall. The drop in temperature caused by the depletion of atmospheric carbon dioxide combined with the astronomical position of the Earth at the furthest point of its elliptical path around the sun conspired to generate an ice age. Why ice ages of the past (Table 1.3) came to an end is another question that must relate to the carbon cycle, at least to some extent equally enigmatic are the issues of when and why the current ice age will end. 

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