9 . Methane (甲烷) is a greenhouse gas. Over 20 years it has over 80 times the planet-cooking power of carbon dioxide, and is _________ for nearly 45%of warming today. Because methane is the main _________ of natural gas, much of man-made emissions comes from the energy industry. Yet because it is short-lived, controlling methane offers the world its best possible chance for _________ progress against climate change.

As COP28, the UN’s climate summit, gets _________ in Dubai, it is greatly encouraging, therefore, that the chances of such a deal on methane are good. Negotiators must _________ at a rare opportunity to strike one.

The reason a deal looks possible is that the politics are promising in all the biggest markets. China has recently announced that it will start including methane in its national climate plans. America will soon finalize regulations to _________ methane emissions from its huge oil and gas sector, including measures that cover leaky pipelines and storage. And the European Union has also agreed on tough methane standards, covering both domestic sources and _________ fossil fuels.

_________ are helping, too. A range of new technologies for monitoring methane will help _________ large sources of emissions from the energy industry. Because oil and gas firms can often sell methane (rather than wastefully burning or releasing it), many investment s to avoid __________ will pay for themselves. Most firms do not invest because of the trouble, higher returns on other projects, or wells’ distance from consumers. Whatever the reason, they suffer no __________ for adding needlessly to global warming.

Since green-washing, the process of conveying a false impression about how some products or measures are environmentally sound, is quite common, if a global methane deal is to be more than that, __________, it will need rigour (缜密). Methane-control seemed to __________ at the UN climate summit in Glasgow two years ago, when negotiators __________ came up with a proposal to cut emissions by 30% by 2030．Yet the deal was voluntary, and had no enforcement mechanisms (机制); emissions have since __________. An agreement this time round must link promises to national climate plans and, crucially, to domestic enforcement mechanisms.

From roughly the 16th to 19th centuries, much of the Earth was caught by a persistent freezing cold. During this time, the Northern Hemisphere (半球) experienced long stretches of temperatures so cold that people witnessed crops     1     and rivers freezing — like the Scheldt River. Thousands of people walking and playing across the frozen River Thames; Soldiers on horseback seeing ships     2     in the ice; Natives using snowshoes to outsmart the English army…These were some of the images that define the Little Ice Age — a period of several centuries last millennium in which parts of the Northern Hemisphere struggled with a(n)     3     cold. But what caused the Little Ice Age, how long did it last, how did people     4     to the freezing cold — and what lessons can we learn as we enter our own period of climatic change?

The Little Ice Age was not a true ice age —     5    cooling was probably only in the order of 0.5 degrees Celsius, or 1 degree Fahrenheit — or was it consistently cold. Dagomar Degroot, associate professor of environmental history at Georgetown University has     6    to the era as a series of “little ice ages.”

Although some researchers argue it may have begun earlier, NASA defines the Little Ice Age as beginning around 1550 and     7     of three cold peaks-around 1650,1770 and 1850.

Scientists are still working out     8     what caused the Little Ice Age too. Theories     9     from decreased solar activity to increased volcanic eruptions, to the decline of populations in North America, which allowed forests to replace agricultural land, in the process removing about seven billion tons of carbon from the atmosphere. A 2022 study argued that the     10     trigger was actually a rise of extremely warm water flowing north from the tropics in the late 1300s,which pushed Arctic ice into the North Atlantic.

Whatever the cause, the consequences of the Little Ice Age have a lasting effect on history, although to what extent is still controversial.