As I write this post, 104 recent fires have burned more than 2.4 million acres in 12 U.S. states. More than 25,000 firefighters are fighting these fires. California is particularly hard hit by fires. The Caldor Fire has burned more than 20,000 acres and the Dixie Fire over 48,000 acres. The fire season in the western states usually lasts from July till December and this is only the second month into this six-month long season.
This year’s severe fire season is not unique. In 2020, record-breaking fires broke out in California, Oregon, and Washington. Fanned by strong, gusty winds and fueled by hot, dry vegetation, these fires burned more than 10.2 million acres, killed 37 people, and caused $16.5 billion in property damages and $3.3 billion in fire-fighting costs. Hundreds of thousands of people fled their homes.
Wildfires have been setting new records for several consecutive years. For example, in 2018, after a summer with record-breaking heat and only half of the usual rainfall, a wildfire turned a small town called Paradise on a Sierra Nevada slope into hell. This fire destroyed 14,000 houses and killed 85 people.
Wildfires are a global phenomenon. There were more than 70,000 forest fires in Brazil in 2019. In early 2020, Australia experienced the worst wildfire season ever. More than 15,000 fires caused nearly 3 billion animals to be burned to death or forced to flee their habitats. Since July this year, several hundred fires have been burning in Siberia, covering thousands of square kilometers.
Wildfires are usually caused by lightning or human activities such as bonfires, arsons, and burning of vegetation. As more people choose to live near wooded areas, wildfires have become more frequent. Data show that climate has become drier and warmer in the past few decades and the earth’s atmospheric circulation has subsequently changed. These changes make the wildfire season start earlier and last longer, and fires burn more strongly. A 2015 analysis found that from 1972 to 2013, global wildfire season increased in length by an average of 20%, and the global burned area more than doubled. The wildfire season in the western U.S. used to be from August to November, and now there are fires year round.
In the past two hundred years, humans have burned large amounts of fossil fuels (such as coal, gasoline, and natural gas) in transportation, industry, and electricity generation. CO2, together with other greenhouse gases, absorbs heat that the earth emits back to space, and then radiates back to the atmosphere and the earth’s surface. This back radiation increases the temperature of the atmosphere and the earth’s surface. Two hundred years ago, the atmospheric CO2 level was 275 parts per million (275 ppm). It has now reached over 410 ppm and is rising by 2.5 ppm every year. This effect makes the global average temperature 2 F higher than before industrialization and has changed the atmospheric circulation and ocean temperature. This is climate change. Recent research has shown that climate change has altered the geographic distribution of rainfall as well. As a result, flooding has increased in some areas, while other areas have become drier.
At the same time, tropical cyclones are strengthening under climate change. Over the past few years, super hurricanes in the Western Atlantic, the Caribbean, and the Gulf of Mexico have become commonplace. Nine out of ten of the most destructive Atlantic hurricanes occurred in the 21st century.
In August 2017, Hurricane Harvey hit Houston with 130 mph wind, affecting 13 million people, flooding 135,000 homes, and damaging nearly one million cars. In September of the same year, Hurricane Maria, with 155 mph wind, destroyed the entire Puerto Rico Island. Maria caused 3,000 to 4,000 deaths and $90 billion in losses. It is estimated that hundreds of thousands of residents moved out of Puerto Rico every year after Maria. From 2017 to 2019, Puerto Rico lost as many as 470,000 residents, or 14% of the total population. In August 2018, Hurricane Dorian, with 185 mph wind, killed more than 70 people in Bahamas and damaged 13,000 homes. Dorian was a rare super hurricane and the worst natural disaster in Bahamas history. In October 2018, Hurricane Michael, with 160 mph wind, made landfall in Florida.
Tropical cyclones in the Atlantic Ocean originate as waves in the westward air currents. They intensify into hurricanes in the warm water of the Western Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico. The genesis of tropical cyclones does not require climate change. However, climate change has made the atmospheric and ocean conditions more favorable for cyclones to intensify into hurricanes.
On the other side of the planet, record-breaking floods have happened in two consecutive years. Between June and September of 2020, heavy rainfall in China caused floods in large span of southern China. By the end of June, floods had affected more than 10 million people in 26 provinces and cities. By August, there were 443 rivers with flooding water across China, and the water level of 33 of them reached the highest point in history. These floods affected 63 million people, with $26 billion of direct economic losses, 219 people dead or missing, and 540,000 houses collapsed.
In July this year, heavy rain caused multiple floods to break out in China’s Henan Province. The heaviest rainfall of nearly 8 inches per hour was recorded. By early August, 302 people were recorded dead, 50 more went missing, over 1 million people were evacuated, and over 9 million people were affected. At almost the same time, severe floods broke out in several European countries (UK, Austria, Belgium, Germany, Netherlands, and others), killing 230 people in total.
Some people have fled from hurricanes, wildfires, or floods; others have migrated in search of water for survival. A 2017 study by the East Anglia University in UK found that by 2050, if the global temperature rose by 2 C, a quarter of the earth’s land would suffer severe drought and desertification. Early signs are ominous: the Brazilian city of São Paulo almost ran out of water in 2016. The same was true of Cape Town, South Africa in 2018. In the fall of 2018, a record drought in Germany dropped the water level of the Elbe River below 20 inches, resulting in a 40% reduction in corn production. The groundwater in the world’s grain-producing regions has begun to dry up. This year, much of the western U.S. is in the grip of a severe drought of historic proportion and drought emergencies have been declared in many areas. Without other irrigation methods, the 1930s Dust Bowl condition might repeat itself. During the Dust Bowl period, farmers were forced to relocate to California; but California is no longer an oasis now.
Droughts, hurricanes, wildfires, and floods are all related to climate change. Climate change has altered atmospheric and ocean conditions, making these disasters more frequent, more severe, and lasting longer. These new signs show that the natural environments are deteriorating under climate change and the necessary resources for human survival are coming up short.
I have adopted the title of Dr. James Hansen’s 2009 book “Storms of My Grandchildren” as the title of this post. Hansen, a NASA climate scientist at the time, is perhaps best known for bringing climate change to the world’s attention in the 1980s. In just 12 short years after the book, his prediction of his grandchildren’s climate catastrophe has become our generation’s most pressing danger.