U.S. Billion-dollar weather and climate disasters over the last 40 years (1980-2019) - in historical context

NOAA’s National Centers for Environmental Information (NCEI) tracks U.S. weather and climate events that have great economic and societal impacts (www.ncdc.noaa.gov/billions). Since 1980, the U.S. has sustained at least 250 separate weather and climate disasters where the overall damage costs reached or exceeded $1 billion (including adjustments based on the Consumer Price Index, as of July 2019). The cumulative cost for these 250 events exceeds $1.7 trillion.

During the first six months of 2019, the U.S. experienced two major inland floods and four severe storm events - each with total, direct costs exceeding $1 billion. This follows a very active year in 2018, in which the U.S. was impacted by 14 separate billion-dollar disaster events: two tropical cyclones, eight severe storms, two winter storms, drought, and wildfires. The 14 separate U.S. billion-dollar disasters in 2018 represented the 4th highest total number of events trailing only the years 2017 (16 events), 2011 (16) and 2016 (15). The most recent years of 2018, 2017 and 2016 have all been historic in the number of billion-dollar disasters that have impacted the U.S. – totaling 45 separate events. This is a 3-year average of 15 disaster events / year, the highest on record, and well above the annual inflation-adjusted average of 6.3 events per year (1980-2018).

The year 2018 also experienced the 4th highest total costs ($91.0 billion), as noted below in the time-series link. The combined costs of the 2018 disasters trails only the years 2017 ($312.7 billion), 2005 ($220.8 billion) and 2012 ($128.6 billion) when all years are inflation-adjusted to 2019 dollars. The annual cost average for billion-dollar disasters is $43.6 billion (CPI-adjusted) over the period of record (1980–2018). The annual cost average over the last 5-years (2014–2018) is $100.8 billion (CPI-adjusted), more than double the long-term average. This 5-year average annual cost is indicated by the black line in the following time-series.

Focusing on the last 3 years (2016-2018) - the U.S. experienced disaster costs exceeding $150 billion / year – also a new record. In addition, these costs represent a conservative measure of what is truly lost but cannot be fully measured given data limitations. For example, we do not account for natural capital losses, healthcare-related costs, all downstream (indirect) costs or statistical values associated with loss of life.

It is also of note that these estimates do not reflect the total cost of all U.S. weather and climate-related events, only those associated with events in excess of $1 billion in damages. However, these extreme events do account for the majority (>80%) of the damage from all recorded U.S. weather and climate events (NCEI; Munich Re). Moreover, these billion-dollar disaster events are becoming an increasingly larger percentage of the cumulative damage from the full distribution of weather-related events at all scales and loss levels. Clearly, the historically large U.S. losses from hurricanes and wildfires over the last few years have further skewed the total distribution of extreme weather costs.

• 1980-2000 ...(~75% of full distribution)
• 1980-2010 ...(~80% of full distribution)
• 1980-2019 ...(~85% of full distribution):
• $1.7 trillion of $2.0 trillion in total US weather and climate events cost

Examining the bigger picture

One of the most striking comparisons among U.S. billion-dollar disasters over the last three years is the series of hurricane impacts. From 2016-2018, the U.S. was impacted by 6 separate billion-dollar hurricanes (i.e., Matthew, Harvey, Irma, Maria, Florence, Michael) with an inflation-adjusted loss total of $335.8 billion and 3,318 fatalities. As a comparison, the U.S. also experienced a series of active hurricane seasons from 2003-2005 where 9 separate billion-dollar hurricanes (e.g., Charley, Ivan, Katrina, Rita, Wilma, etc.) made landfall, with an inflation-adjusted loss total of $303.0 billion and 2,225 fatalities. These losses are a reminder that individually, hurricanes have historically been the most damaging and costly weather events to affect the United States.

Even so, there is no modern comparison regarding the scale and cost of the 2017 and 2018 Western wildfire seasons. In total, over 18 million combined acres burned in 2017 and 2018, with costs in excess of $40 billion. The total U.S. wildfire costs for the last two years is roughly equal the costs of the previous 37 years combined (1980-2016). On average U.S. wildfire seasons have caused damage on the order of $1.0-2.0 billion annually.

The rising frequency of billion-dollar disaster events

The U.S. has experienced a rising number of events that cause significant amounts of damage. From 1980–2018, the annual average number of billion-dollar events is 6.3 (CPI-adjusted). For the most recent 5 years (2014–2018), the annual average is 12.6 events (CPI-adjusted). The increase in population and material wealth over the last several decades are an important factor for the increased damage potential. These trends are further complicated by the fact that many population centers and infrastructure exist in vulnerable areas like coasts and river floodplains, while building codes are often insufficient in reducing damage from extreme events. Climate change is also paying a role in the increasing frequency of some types of extreme weather that lead to billion-dollar disasters—most notably the rise in vulnerability to drought, lengthening wildfire seasons in the Western states, and the potential for extremely heavy rainfall becoming more common in the Central and Eastern states. Each of these changes in extremes are becoming more visible in relation to the influence of climate change (NCA 2018).