http://tags.library.upenn.edu/tag/NYTimes+biofuel PennTags Feed http://tags.library.upenn.edu/makerecord/url/24349 http://tags.library.upenn.edu/makerecord/url/24349 February 8, 2008<br />Biofuels Deemed a Greenhouse Threat<br />By ELISABETH ROSENTHAL<p>Almost all biofuels used today cause more greenhouse gas emissions than conventional fuels if the full emissions costs of producing these &quot;green&quot; fuels are taken into account, two studies being published Thursday have concluded.</p><p>The benefits of biofuels have come under increasing attack in recent months, as scientists took a closer look at the global environmental cost of their production. These latest studies, published in the prestigious journal Science, are likely to add to the controversy.</p><p>These studies for the first time take a detailed, comprehensive look at the emissions effects of the huge amount of natural land that is being converted to cropland globally to support biofuels development. </p>