Read the following passage. The Eocene epoch began 55 million years ago with a rapid increase in global temperatures, the Eo

Unfortunately, none of the theories presented in the reading selection adequately explains the Eocene warming.
    First, about the warming effect of the change of ocean currents, it’s true that these changes would have caused some warming. However, we did some computer modeling of the currents. The computer models show that even when the ocean currents started flowing in new directions, they could still transport only a relatively limited amount of heat. The amount of heat they transported was much smaller than the amount of heat needed to cause the Eocene warming, so the ocean current theory does not seem to work.
    Second, the comet theory. At first, the clay layer with magnetic particles was thought to indicate a comet collision. However, new findings tell a different story. The magnetic particles in the clay did not come from a comet collision, but were actually produced by primitive one-celled organisms, a kind of bacteria. The magnetic particles were the only evidence for the comet hypothesis. Without that evidence, the comet theory collapses.
    As for the third theory about methane, the problem is timing. See, what the reading does not make clear is that after the oceanic methane starts escaping, it still takes thousands of years for it to build up in the atmosphere and create a greenhouse effect. So, we would expect that the atmospheric warming happened thousands of years after the methane started escaping, but that’s not what geological data show us. The data show that the climatic warming started happening at the same time as the escape of methane. Since the warming started at the same time and not thousands of years later, it could not have been caused by a slow accumulation of methane in the atmosphere.