A Song of Melting Ice and Fire Pt. 1:
How America’s Extreme Summer weather is exacerbated by climate change
A Time of Woes
America is facing many concurrent disasters that are all coming to a head simultaneously. Long frozen social and economic unrest has burst forth this year with vigor amidst simmering economic, democratic, and epidemiological crises. We remain in the throes of a deadly pandemic that has killed 180,000 Americans and have 45,000 new Covid-19 cases per day. The Trump administration vies for a spot in the next edition of Merriam-Webster’s dictionary under inept with its woeful pandemic response: the dashes of misinformation (lies), splashes of sabotaging/delaying action that could’ve saved tens of thousands of lives, and heaps of prioritizing the economic recovery of America’s wealthiest over the working class and small businesses all merit consideration as widespread reckless endangerment of human life. Conversely, the Trump administration is hosting a master class in how to rig an election. They stand on the shoulders of gerrymandering Republican giants, as they oppose funding the post office, remove USPS sorting machines in towns that voted for Clinton in 2016 (many in swing states), and peddle demonstrably false (“7–8 cases per year” nationally) lies about mail-in voter fraud (while voting by mail themselves). NBA players boycotted playoff games over ongoing police killings of African Americans and lack of justice for the victims: George Floyd, Breonna Taylor, and Jacob Blake to name a few. Compounding matters, extreme right wing fascists, some associated with the boogaloo movement, have been behind various shootings and terrorist attacks so far this year.
A Rash of Extremes
In 2020, weathering the ongoing storm of social disasters has been exhausting. Unfortunately, these social storms are not the only ones we’re facing. Actual storms like inland ‘hurricanes’, pyrocumulonimbus fire tornadoes, record breaking hurricanes, and massive heat waves have all laid siege to the nation in the past ten days or so. The extreme weather concurrently assaulting the nation is no mere coincidence. Climate Change plays a strong role in many if not all of these extreme weather events. The past 12 months have been the warmest consecutive 12 month stretch in recorded history, at 1.28°C above pre-industrial temperatures. The resulting physical changes to the Earth, manifesting in melting ice and fiery temperatures, impact the intensity of our current extreme weather onslaught.
A Swarm of Storms
A few days ago, Hurricane Laura underwent rapid intensification into a category 4 hurricane, the most rapid in the Gulf of Mexico history. It took merely 2 days for Tropical Storm Laura to become Hurricane Laura with 150 mph winds. It’s peak sustained winds intensified by about 75 mph in one 24-hour stretch. Laura made landfall near the Texas and Louisiana border around midnight August 27th, with wind speeds of 150 mph. Scientists and NASA forecasted the storm surge could penetrate 40 miles inland. Worsening matters, the peak storm surge was predicted to be between 15–20 feet. Lake Charles, a Louisiana town of 78,000 people, could have been completely inundated. Fortunately, the eye of the storm was a little too far East to allow for a more damaging storm surge to reach Lake Charles. Despite this ‘luck’ the damage is still catastrophic and estimated to be in the billions.
The wrecked neighborhood pictured near Lake Charles is unsurprising given Hurricane Laura is the strongest landfalling hurricane in Louisiana for over 100 years. In the forecast impact zone, an estimated 750,000 people were told to evacuate due to what the National Hurricane Center called, “Unsurvivable storm surge”. Hurricane Laura is officially tied at first for the most intense hurricane in Louisiana history, with the strongest winds at landfall (and possibly the third lowest pressure).
Many people are unclear on how climate change could impact Hurricane Laura. The truth is climate change exacerbates the impact of hurricanes like Laura in a variety of ways. First, global average temperatures the last 12 months were about 1.28°C above average, and the water in the Gulf of Mexico along Laura’s path is about 1.0°C above pre-industrial average temperatures.
While it may not seem like much, that extra heat in the ocean and atmosphere has a big impact. Ocean waters above 27.8°C fuel and strengthen hurricanes. Much of the Gulf of Mexico is near or above 30°C presently, contributing greatly to Laura’s rapid intensification. The extra 1°C warming in the Gulf of Mexico relative to pre-industrial temperatures (the above image is with respect to the 1971–2000 baseline, not pre-industrial average T) added fuel to Hurricane Laura that most likely wouldn’t have been there absent human-driven climate change signal.
Climate change makes hurricanes more extreme in other ways as well. The IPCC estimates that “tropical cyclone precipitation rates (for a given storm) will increase by at least 7% per degree Celsius sea surface temperature warming (SST), owing to higher atmospheric water vapor content” due to the atmosphere’s ability to hold more moisture at higher temperatures. As the planet has warmed, glaciers and ice sheets are contributing to sea level rise. Earlier this Summer, two teams of scientists published research demonstrating that the Greenland Ice Sheet has switched to “a new dynamic state of sustained mass loss”, and that temperatures over Antarctica have warmed rapidly over the past few decades. When combined with imaging from NASA’s GRACE satellite measuring the ice sheets gravity showing ice mass loss, it’s clear melting ice from both is contributing to sea level rise. Since every hurricane now occurs in a world with higher sea levels, hurricanes storm surge penetrates further inland than they would without the extra heat. Furthermore, a handful of scientific papers published earlier this year find strong evidence that the intensity and frequency of strong hurricanes like Laura has already increased. When America experiences extreme weather such as Hurricane Laura, the role of climate change is unmistakable.
Image credit: left, NASA Earth observatory; right NWS National Hurricane Center (NCEP NOAA)
To be clear, that doesn’t mean that intense hurricanes couldn’t or didn’t happen in the past. However, the extra degree of warming increases the probability that hurricanes traverse warm enough Sea Surface Temperatures (SST’s) to strengthen themselves, both in terms of where they can form and when they can form. Hurricane intensity isn’t the only record Laura is breaking, it’s also the earliest ever Atlantic basin L-Storm (12th tropical storm of the year) in records going back 170 years. Indeed, from Edouard to Marco, the 5th to 13th tropical storms this year have ALL been the earliest on record, generally beating the old record from 2005 — precisely what you’d expect as ocean temperatures increase and a larger percentage of the year has warm enough SST’s to allow for hurricane formation. It shouldn’t be surprising then, that Laura nearly toppled 2005’s Katrina for most intense hurricane to hit Louisiana.
A Heat that Grows
As noted, hurricanes aren’t the only extreme weather bedeviling America in our fiery world. Just before Hurricane Laura, the Western US wilted under heat wave Beelzebub. Indeed, preliminary reports indicate that a station at Furnace Creek in Death Valley broke the record for warmest temperature in world history at 130°F, or 54.4°C (other candidates have serious flaws to their claims). The record-breaking heat in Death Valley is the product of a massive ‘heat dome’ that settled over California a couple weeks back and hasn’t left yet.
This heat dome is not only behind Heat Wave Beelzebub and the record breaking heat in Death Valley (there’s debate over naming heat waves to help build awareness of the associated danger to human life). It’s also behind the spawning of a fire tornado (pictured above) in North East California and a major contributor to Phoenix’s record-breaking string of days over 110°C at 49 times so far this year. Relatedly, the severe and extreme drought parching the US West is exacerbated by Beelzebub. The heat wave didn’t cause the drought, but certainly made it worse.
Similarly, climate change didn’t ‘cause’ Heat Wave Beelzebub. Like hurricanes, heat waves existed before climate change. However, climate change DOES increase the probability of high heat temperature anomalies occurring, and just how hot it gets when heat waves do occur. Recalling that global average temperature has been about 1.28°C above the pre-industrial average over the past 12 months, it’s safe to say that the odds that America would experience a record-breaking heat wave of Beelzebub’s caliber were high. In the image below from Dr. James Hansen of Columbia, the increasing frequency and mean intensity of extreme heat is readily apparent. The 2009–2019 average heat temperature is about 1.5 standard deviations higher than the 1951–1980 average for June July and August.
There’s also some evidence that suggests melting arctic sea ice is making heat waves and drought in the US West more likely. The authors of a 2017 paper identify how “sea-ice changes lead to reorganization of tropical convection that in turn triggers an anticyclonic response over the North Pacific, resulting in significant drying over California”. Most of the summer, Arctic sea ice has been at or near a record low extent, and the average sea ice extent has decreased every decade. It’s current extent in August is already below the mean yearly low typically observed in September during the 2010’s .
It should go without saying, but the melting ice in the Arctic Ocean is being driven by Arctic temperature anomalies that are a whopping 3°C-5°C above the 1951–1980 average. The ensuing ice melt, along with the baseline high heat in the Southwest contributes to making Beelzebub worse. Just as Hurricane Laura is impacted by climate change, Beelzebub is almost certainly hotter than it would’ve been absent the 1.28°C warming signal from human-caused climate change. In this song of melting ice and fire, there is a common songwriter: climate change.
An Advance of Conflagrations
We may not have fire-breathing dragons in the real world, but we do have increasingly dangerous wildfires. Around the world, wildfires in California, Australia, and Siberia have broken records for area burned over the past few years. It’s starting to feel like clockwork, with massive wildfires in the Northern Hemisphere Summer followed six months later by unprecedented wildfires in the Southern Hemisphere. There is a common trend: in each of these events, record breaking heat precedes the outbreak of these wildfires.
A couple weeks ago, residual moisture from Tropical Storm Fausto caused a lightning blitzkrieg in California during Heat Wave Beelzebub. California saw over 10,000 lightning strikes in a matter of days, which led to hundreds of wildfires. In one week, the lightning sparked wildfires that displaced over 120,000 and burned a million acres, more burned area than the State typically experiences over the whole year. Amazingly, these fires have started at the beginning of California’s wildfire season, which typically lasts from August-November. The SCU and LNU lightning complex fires — so named because many smaller fires merged into so-called ‘gigafires’ — are competing to be the 2nd largest fire in California’s history. They may well pass 2018’s Mendocino Complex Fire for largest in California’s history, and are both under 40% contained. The LNU complex isn’t strictly massive, it’s also in the top 20 for most deadly fires and most buildings destroyed.
The smoke from the California’s wildfires yielded air quality that was the worst in the world, and eventually spawned a cloud that stretched across the Rockies, the Midwest, and reached the East Coast. Many farm and/or migrant workers suffered from persistent smoke trapped by the heat dome in California’s central valley. In the Santa Cruz mountains, the CZU complex fire is still burning. As it approaches the city of Santa Cruz, some firefighters staving it off have lost their own homes as the conflagration advances through the mountains. As noted on “The Climate Pod” podcast, firefighters statewide have to take extra precautions due to Covid-19, with more social distancing and isolation on the front lines. The conjunction of intense fires and Covid-19 stresses at the gates of hell has some firefighters contemplating leaving the State.
Complicating matters, California reported 12,614 new Covid-19 cases on August 15th, and has had over 6,000 new cases per day for the duration of the fires. As Professor Leah Stokes of UC Santa Barbara noted, “I don’t want to live in a world where we have to decide which mask to wear for which disaster, but this is the world we are making”. Some of California’s counties with the most Covid-19 cases are in the Central Valley, where the heat dome has been trapping smoke from the wildfires. Omnipresent smoke during a horrendous respiratory-spread pandemic is nightmare material for public health officials. It remains to be seen if the simultaneous presence of smoke and local outbreaks will lead to more deaths from Covid-19 than the base case fatality rate observed thus far.
The spread of Covid-19 in the Central Valley alongside wildfire smoke has always been one of the biggest concerns for climate change, that it would be a “threat multiplier”. Just as Hurricane Laura and Heat Wave Beelzebub were exacerbated by climate change, so too are the record breaking California wildfires. The same record temperatures over the past 12 months, a full 1.28°C above pre-industrial average temperatures, literally ‘fueled’ this fire. As Dr. Cristina Santin notes, ““In the fire community, we call vegetation that is available to burn ‘fuel’,” which in turn helps fires spread quickly over large areas. It helped cause the heat wave that dried out trees across California and made them more likely to burn when lightning struck. The extra heat in the atmosphere from both the heat wave and the global temperature increase backing it pull more moisture out of the ground and plants. Consequently, there is a vapor pressure deficit, which as Dr. Daniel Swain notes is the “gap between how much moisture *could* be in the air vs. how much is *actually there*.” Compounding the problem, global annual average land temperatures have consistently been about 60% warmer than global land & ocean temperatures for the past 40 years. Last year, global land temperatures were about 1.9°C above the pre-industrial average. This extra heat provides ample fuel for devastating wildfires.
Heat waves like Beelzebub are driving wildfires around the world that are increasingly being attributed to climate change. A 2018 fire in Greece would’ve been impossible without climate change. Similarly, Dr. Friederike Otto and the Environmental Change Institute found that climate change made Australia’s Summer fires 30% more likely. That same team just released an attribution study that determined the Siberian heat wave of 2020 that triggered widespread Arctic fires earlier this summer would’ve been “almost impossible without climate change”. Another study published days ago establishes that climate change is increasing the likelihood of extreme Autumn fires in California. Furthermore, they observed a doubling of “Autumn fire weather days” has doubled since the 1980’s, and their climate models indicate that further climate change and associated temperature increases will lead to even more days with extreme fire weather.
There are other, less obvious ways climate change may be contributing to the wildfires scorching California (and Colorado, which just recorded its largest wildfire on record). The lightning siege that initiated many of California’s fires this year may have climate change roots. One paper found that lightning strikes in the United States would increase by about 12% per degree Celsius of global warming. As Dr. Jeff Masters notes, “Scientists can’t yet say whether climate change played a role in the rare lightning storms that ignited the August 2020 fires”. However, there is no doubt that global land temperatures being nearly 2°C hotter plays a role in drying out vegetation for when lightning strikes do occur, allowing them to spark fires that spread more widely and rapidly.
Counter intuitively, an observed increase in winter rainfall may increase wildfire risk for California. The increased precipitation increasingly falls as rain instead of snow in our 1.28°C warmer world, which help vegetation grow more in the spring only to be dried out further by increasingly hotter and drier summers. When there’s less snow pack melt water run-off during the year, the vegetation that burst forth in Spring quickly turns to more fuel for California’s fires. High precipitation in the winter followed by extremely hot and dry summers create what Dr. Swain calls “precipitation whiplash events”, creating conditions that turn much of the state into a tinder box. Precipitation whiplash may be driving the surprising ‘re-burning’ of lands in California that had just burned a mere 1–3 years prior.
Similarly, a study published in April this year found that climate change “pushed what would have been a moderate drought in Southwestern North America into megadrought territory”. The authors add that the drought from 2000–2018 was the second driest drought since 800 CE, and that climate change accounts for 47% of the drought severity. Other studies have found that the extra warming from climate change makes megadroughts more likely in general, and the risk will increase the more the world warms. Given that the megadrought from 2000–2018 was the worst in over a millennium and reduced precipitation while increasing heat, one can see how climate change creates the underlying conditions to allow for the record breaking wildfires of 2018 and 2020.
A final odd potential contributor to how climate change impacted California’s recent fire outburst is Arctic sea ice melt. In addition to Arctic sea ice melt contributing to atmospheric ridges forming off the coast of California, there is a growing body of evidence that melting Arctic sea ice contributes to the jet stream getting ‘stuck’ in a high amplitude wave. When the jet stream gets stuck, it can cause heat waves like the one over California to just sit in one place for weeks. In an email exchange between Dr. Michael Mann and Dr. Jeff Masters, Mann suggested that Heat Wave Beelzebub resembles the ridge that contributed to the extreme heat fueling the 2018 California fires.
A Swarm of Storms
Just as climate change contributed to Hurricane Laura, Heat Wave Beelzebub, and the wildfires in California, it will continue to contributing to extreme weather as we move into Autumn. While the hottest temperatures of the year are likely behind us, hurricane season is just hitting it’s apex and lasts into November. Likewise, California’s fire season doesn’t usually flare up in earnest until the Fall. The now annual record-breaking Swarm of Storms has only just begun this year. Extreme weather events will continue to occur every year in record-breaking fashion until we stop climate change by ending fossil fuel use across the planet. Until then, the song of melting ice and fire will go on. On that note, in the style of George R.R. Martin, Part 2 of “A Song of Melting Ice and Fire” should get published any day now…
