cover of episode How weather ‘whiplash’ is driving floods and fires

How weather ‘whiplash’ is driving floods and fires

2025/1/14
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Albert van Dijk
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Madeleine Finlay
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Madeleine Finlay: 我观察到加州今年的野火不同于往年，它们发生在冬季，持续时间长达八个月没有降雨，导致植被极其干燥，易于燃烧。加州在创纪录的降雨后经历了长时间的干旱，这导致植被茂盛生长后迅速枯萎，成为野火燃料。气候变化导致全球水循环不稳定，出现极端干旱和极端降雨交替出现的“天气骤变”现象。气温上升加速了水循环，如同引擎超速运转，导致极端天气事件增多。极端干旱和极端降雨交替出现的“天气骤变”事件越来越频繁。加州2022-2023年的创纪录降雨导致植被茂盛，随后干旱导致植被变成易燃物，引发了今年的野火。“天气骤变”还会导致其他连锁反应，例如快速融雪导致洪水，以及洪水后高温导致疾病爆发。我们必须停止燃烧化石燃料，并为洪水、野火和干旱做好准备。气温上升导致天气模式变得不可预测，例如加州冬季发生野火。为极端天气做好准备很困难，例如洛杉矶的野火就因为缺水而难以扑灭。更好的水资源管理对于应对极端天气至关重要，但解决方案因地制宜。 Albert van Dijk: 全球水循环监测报告显示，极端强降雨和极端干旱的趋势越来越明显。气温上升导致既有极端干旱，也有极端降雨，这并非矛盾。大气层就像海绵，吸收水分后会在其他地方释放，而气温上升使得大气层吸水能力增强，导致干旱和暴雨交替出现。气温上升使大气层吸水能力增强，导致干旱加剧，而当大气层释放水分时，则会造成更强烈的降雨。气候变化不仅影响大气层的水分含量，还影响气流和天气系统，加剧极端天气事件。加州的野火是“天气骤变”的典型例子，先是大雨导致植被生长，随后干旱导致植被干燥易燃。澳大利亚的“黑色夏季”野火也是“天气骤变”的例子，先是大雨，随后是极端高温导致快速干旱。气候变化的不确定性是科学家们担忧的问题，因为我们无法预测地球会发生什么。亚马逊雨林的干旱和火灾就是一个例子，它释放的温室气体加剧了气候变化。气候临界点是不可逆转的，我们必须尽快停止燃烧化石燃料。天气模式变得不可靠，例如农作物在早春生长后遭遇寒流受损。如何管理水库以应对干旱和洪水是全球性的挑战。

Deep Dive

Key Insights

What is weather whiplash and what causes it?

Weather whiplash refers to rapid swings between extreme weather conditions, such as droughts and floods. It is caused by an increasingly erratic water cycle driven by rising temperatures. The atmosphere can hold more moisture, leading to intense droughts when it absorbs water from the surface and severe flooding when it releases that moisture.

How has climate change affected the global water cycle?

Climate change has accelerated the global water cycle due to rising temperatures, which increase evaporation and the movement of water. This has led to more extreme weather events, including both heavy rainfall and prolonged droughts, as the atmosphere becomes 'spongier' and holds more moisture.

Why are wildfires in California occurring during winter?

Wildfires in California are occurring during winter due to weather whiplash. Record-breaking rainfall in late 2022 and early 2023 led to significant vegetation growth, followed by an unusually dry rainy season in 2023-2024, which turned the vegetation into kindling, fueling the fires.

What are the compounding consequences of weather whiplash?

Weather whiplash can lead to a range of compounding consequences, including rapid snowmelt causing flooding, outbreaks of waterborne diseases after floods, and increased wildfire risks due to vegetation drying out. It also accelerates climate tipping points, such as the release of greenhouse gases from events like Amazon fires.

How much has the frequency of weather whiplash events increased since the mid-20th century?

Since the mid-20th century, weather whiplash events occurring within three months have increased by between 31% and 66%, according to a study published in Nature.

What role does the atmosphere play in extreme weather events?

The atmosphere acts like a sponge, absorbing and releasing moisture. Rising temperatures increase its capacity to hold water, intensifying droughts when it absorbs moisture and causing extreme rainfall or flooding when it releases it. This dynamic is a key driver of extreme weather events.

What are the challenges of managing water resources in the face of weather whiplash?

Managing water resources during weather whiplash is challenging because it requires balancing between droughts and floods. For example, empty dams can capture floodwaters but cannot supply water during droughts. Localized solutions are needed, depending on the specific water systems and needs of each region.

Chapters
The episode starts by describing the devastating wildfires in Los Angeles and connects them to the phenomenon of weather whiplash. It introduces the concept and its relation to rising temperatures and the erratic water cycle.
  • Wildfires in Los Angeles, California destroyed homes, ecosystems, and cost lives.
  • The fires are occurring in winter, during a typically wet month.
  • The phenomenon of weather whiplash, characterized by rapid swings between extreme weather events, is discussed.

Shownotes Transcript

As wildfires continue to cause devastation in Los Angeles, Madeleine Finlay speaks to Albert van Dijk, professor of water science and management at the Australian National University, about how rising temperatures are causing rapid swings in extreme weather. Help support our independent journalism at theguardian.com/sciencepod)