6 . The cold, wet weather of winter often puts out any wildfires that are still burning, but not in the far North areas, such as Alaska, Canada, and other parts of North America. Some forest fires just don’t die in these places. Think of the fires as “zombies” (僵尸): Scientists do. When summers are warmer than normal, some fires can hide through the winter. They burn dead plant matter and soils under snow. In May 2021, scientists reported their work to a scientific journal. The scientists saw that zombie fires are rare but they could become more common as the world warms, the study warns.
“Some years, new fires were starting very close to the previous year’s fire,” explains Rebecca Scholten. She studies Earth and environmental sciences at Vrije University Amsterdam in the Netherlands. The new fires made scientists wonder how often fires might survive the winter. The scientists started by combing through firefighter reports. Then they compared these with satellite images of Alaska and northern Canada. The scientists looked for fires that began close to fires from the year before. They also focused on blazes starting before the middle of summer. Random lightning or human actions spark most fires in the area, Scholten says. But those fires happen later in the year.
Zombie fires accounted for less than 1 percent of the total area burned by fires from 2002 to 2018. But it changed from year to year. Take 2008, for example. A zombie fire burned Alaska that year. It caused almost one-third of fire damage that year. One clear pattern emerged: Zombie fires were more likely to happen after very warm summers. High temperatures may allow fires to reach more deeply into the soil. Such deep burns are more likely to survive to spring.
The zombie fire threat could grow. The climate is warming. Forests in the far North already are warming faster. “We’re seeing more hot summers and more large fires and intense burning,” Scholten says. Plus, zombie fires could cause more issues. The fires release huge amounts of greenhouse gases. These trap heat in the Earth’s atmosphere. The atmosphere is a layer of gases that surround the Earth. Scholten’s research could help fire management. Firefighters would know to check for them after warm summers.
1. What may lead to zombie fires according to the passage?
| A．wet weather | B．hotter summers |
| C．low temperatures | D．cold winters |
2. What can we learn about zombie fires from Paragraph 2?
| A．Where flames broke out provided the clue. |
| B．Changing climate plays a role in the zombie fire threat. |
| C．Zombie fires are less likely to happen after very warm summers. |
| D．It is of little use comparing firefighter reports with satellite images. |
3. What conclusion will be possibly made based on the last paragraph?
| A．It is important to understand zombie fires. |
| B．Zombie fires are likely to be under control soon. |
| C．Firefighters cannot do much to stop the zombie fires. |
| D．We still have much to learn about the warming climate. |
4. Which of the following could be the suitable title of the passage?
| A．“Zombie“ wildfires do great damage to land |
| B．“Zombie” wildfires release greenhouse gases |
| C．“Zombie“ wildfires sparked by human actions |
| D．“Zombie” wildfires reappear after wintering underground |
