Removing carbon dioxide from the atmosphere is essential to meeting international climate goals, scientists say. Without it, it’s all but impossible to reach net-zero greenhouse gas emissions in time to limit global warming to 1.5 or 2 degrees Celsius, the primary targets of the Paris climate agreement.
Yet carbon dioxide isn’t the only climate-warming gas that needs a sharp cutback in the atmosphere. Experts are turning their focus to methane (甲烷) as well.
On Tuesday and Wednesday, the National Academies of Sciences, Engineering and Medicine hosted a workshop dedicated to atmospheric methane removal, which is the process of removing methane emissions directly from the air. The workshop included presentations by dozens of researchers and policy experts addressing questions about the science and effectiveness of methane removal, potential side effects and unintended consequences and the ways it should be governed and regulated.
These presentations will be used to inform a forthcoming NASEM report on atmospheric methane removal. The study will examine the global need for methane removal, viable options for carrying it out and potential risks and benefits, while outlining a road map for future research. The subject is more complicated than carbon dioxide removal, which has received more attention and research.
Methane has a far shorter lifetime in the atmosphere than carbon dioxide, yet it’s a much more powerful greenhouse gas while it lasts. The world already has warmed by more than 1 degree Celsius since the Industrial Revolution, and scientists estimate that methane may be responsible for as much as 0.5 degrees.
Reducing methane emissions at their sources is a growing priority. However, Methane removal, by comparison, is more complex. For one thing, methane is far less abundant in the atmosphere than carbon dioxide, meaning methane capture systems must process much larger quantities of air in order to make a meaningful difference. For another, there are also uncertainties about unintended side effects of some emerging technologies. Adding chlorine (氯) to the atmosphere, for instance, can actually increase the lifetime of methane in the atmosphere if it isn’t carefully dosed. It can also attack the Earth’s protective ozone layer. Besides, chlorine-based methods could decrease certain other types of climate-warming gases in the atmosphere in addition to methane.
【小题1】According to the passage, what is not the issue of the workshop?| A．The effectiveness of methane removal. | B．The side effects of removing methane. |
| C．The predictable results of methane removal. | D．The method of controlling methane removal. |
| A．To persuade the readers to focus on the presentation. |
| B．To inform the readers of the significance of the study. |
| C．To call on the people to reduce the Methane emission. |
| D．To discuss about the problems that may arise from the removal. |
| A．The carbon dioxide has a longer lifetime in atmosphere. |
| B．The methane is harder to be caught because of its traits. |
| C．Scientists have doubts about the effectiveness of the methods. |
| D．The new technologies may bring about the negative effects. |
| A．The NASEM faces a great challenge | B．The methane contributes to global warming |
| C．The government reports on methane removal | D．The scientists explore pulling methane out of air |
