Due to climate change and changes in land use, wildfires are predicted to rise by up to 14 percent by 2030, 30 percent by 2050 and 50 percent by the end of the 21st century, and even areas previously unaffected by wildfires such as the Arctic face increased risk, according to a report by the UN Environment Programme (UNEP) and GRID-Arendal.

The report, “Spreading like Wildfire: The Rising Threat of Extraordinary Landscape Fires”, says that wildfires and climate change are “mutually worsening”. Wildfires are made more serious by climate change through increased drought, high air temperatures, low humidity, lightning and strong winds. Meanwhile, climate change is made worse by wildfires, mostly by damaging sensitive and carbon-rich ecosystems like rainforests.

Wildfires can threaten people’s health and lives, pollute water, destroy crops and reduce land available to grow food. Wildlife, as well as natural habitats, is also rarely spared (幸免). Costs of rebuilding the areas after they are struck by wildfires can be beyond the means of low-income countries. In developing countries, an increase in damaging wildfires may delay progress towards the United Nations Sustainable Development Goals.

The publication calls on governments to adopt a new “Fire Ready Formula”, with two-thirds of spending devoted to planning, prevention, preparedness and recovery and with one-third left for response. Currently, direct response to wildfires typically receives over half of related expenditures (花费), while planning receives less than one percent. “We have to minimize the risk of extreme wildfires by being better prepared: invest more in fire risk reduction, work with local communities, and strengthen global commitment to fighting climate change,” said Inger Andersen, UNEP Executive Director.

The restoration of ecosystems is an important means to reduce the risk of wildfires before they occur. Wetland restoration and the reintroduction of species, building at a distance from plants, and preserving open space buffers (缓冲物) are some examples of the essential investments in prevention, preparedness and recovery.

On the morning of July 4, a magnitude 6.4 earthquake rocked Southern California, destroying roads and sending people fleeing to safety. But that wasn't all the Earth had in store: Less than a day and a half later, a powerful magnitude7. I earthquake shook again. While earthquakes are not unexpected, the two most recent earthquakes are the largest that have struck this area in at least two decades. And a series of large and small aftershocks are expected on the way.

The two earthquakes struck in what's known as the Eastern California shear zone, where the Pacific Plate crushed against the North American Plate. The recent events occurred when two blocks of Earth moved side by side.

They seemed to have occurred along the same set of faults (断层)lying in an area known as the Little Lake fault zone-in most circumstances, earthquakes hit in a familiar order: There's a large earthquake followed by a series of smaller events. That's because the movement that occurs during a large earthquake causes increased force in the surrounding area.

But things are quite different in some circumstances, such as the recent pair of earthquakes in California, a relatively large earthquake just being the forerunner for an even bigger event. While the difference between 7.1 and 6.4 may seem minor，magnitude is a logarithmic (对数的) scale. An increase of a unit of magnitude is about 32 times more energy, which means that the energy the second earthquake released is roughly 11 times that of the first one.

''Fortunately, no deaths or major injuries were reported, '' says Bohon, an earthquake geologist. ''It was in a fairly unpopulated area, although a lot of people felt it'' She suggests people who live in earthquake-prone (地震频发的)areas check how prepared they are for the next event. And she also hopes that the earthquake early warning system can play a good role in saving tens of thousands of lives and schools will popularize the knowledge of geological (地质的) disasters among students.

Earthquakes have rocked the planet for many years. Studying the quakes of the past could help scientists better understand modern earthquakes, but tools to do such work are exiguous.

Enter zircons. Researchers used this special means to home in on the temperatures within a fault (地壳断层) during earthquakes millions of years ago. The method offers insights into the strength of long-ago quakes, and can improve the understanding of how today’s earthquakes release energy, the researchers reported in the April Geochemistry, Geophysics, Geosystems.

“The more we understand about the past, the more we can understand what might happen in the future,” said Emma Armstrong, a professor specializing in earthquakes at Utah State University in Logan. Armstrong and his colleagues focused on California’s Punchbowl Fault. That now-quiet portion of the larger San Andreas Fault was probably active between 1 million to 10 million years ago, Armstrong said.

Heat from friction (摩擦) is generated in a fault when it slips and touches off an earthquake. Previous analyses of preserved organic material suggested that temperatures within the Punchbowl Fault peaked between 465℃ and 1065℃. The researchers suspected that zircons in rocks from the fault could narrow that broad window. Zircons often contain the radioactive chemical elements uranium (U) and thorium ( Th), which decay (衰变) to helium (He) at a predictable rate. That helium (He) then builds up in the crystals. But when a zircon is heated past a temperature criticality value—the size of which depends on the zircon’s composition—the accumulated helium (He) escapes.

Measuring the amounts of the three elements in zircons from the fault suggests that the most in-tense earthquake generated temperatures lower than 800℃. That roughly halves the range previously reported. The finding provides useful clues to the amount of heat released by quakes, something difficult to measure for modern earthquakes because they often occur at great depths. Armstrong plans to continue studying zircons, in the hope of finding more ways to take advantage of them for details about ancient quakes.