Even before Hurricane Harvey began to form, out in the north Atlantic, federal climate experts signalled that 2017 was going to be a bad year for weather and climate catastrophes in America. According to scientists with the National Oceanic and Atmospheric Administration (Noaa), there had already been nine climate and weather-related events that caused more than $1bn of damage.



This “rapid succession of disaster events” from 1 January to 7 July 2017 was part of a years-long increaseand cost a total of $16bn and 57 lives. Such events included flooding in California, Missouri and Arkansas; hailstorms in Colorado and Minnesota; and a sudden, crop-killing spring freeze across South Carolina and Georgia that destroyed an abnormally early fruit blossom.

It is possible that on top of this, economic damage from Harvey will exceed the inflation-adjusted $160bn cost of Hurricane Katrina in 2005, Noaa experts told the Guardian.

But despite Noaa’s work to track what is happening to climate, weather and the oceans, and how society is affected and might react, Donald Trump proposed earlier this year slashing the administration’s budget by almost $1bn. That would cut US and international research as well as funding for other environmental studies and protections.

$1bn disasters in 2017 – before Hurricane Harvey. Photograph: Noaa

From 1980 to 2016, according to Noaa records, the US experienced an average of five and a half $1bn-plus “weather and climate disasters” a year. From 2012 to 2016, that reached 10.6 such events a year. Many such events are increasing in intensity, the agency warns.

Such increases are chiefly due to a combination of climate change and people spreading into vulnerable areas, especially coasts and floodplains. There is an element of chance in where catastrophic weather systems hit, but another important factor is growing prosperity: Americans have more property to be damaged when serious weather strikes.

“The trend in these disasters is clearly up and that reflects more extreme weather events, including more ‘big rain’ events that show up as flooding, and also reflects where people live and how valuable their assets are,” Deke Arndt, chief of the climate monitoring branch of Noaa National Climate Data Center, told the Guardian.

“We are seeing an increase in ‘big rain’ brought by tropical cyclones, thunderstorms and severe weather, and ‘big heat’, where the magnitude and duration of heatwaves are up, and these big events are getting bigger, and are clearly related to the changing climate.”

Noaa’s National Centers for Environmental Information (NCEI) tracks and analyses thousands of weather and climate events across the US every year, examining those “that have great economic and societal impacts”, recording deaths and calculating the estimated cost of each disaster in which damage goes over $1bn.

All $1bn events, by state frequency, from 1980 to 2016. Photograph: Nooa

Since 1980, the NCEI has found that the US has suffered 212 such disasters, collectively costing more than $1.2tn. Texas has had most such events, at 89. The nine events across the US prior to Harvey put 2017 on track to challenge the recent highs of 2016, with 15 such events, and 2011, which saw 16.

The NCEI noted that there were four inland, non-tropical major flooding events causing more than $1bn in damage in the US in 2016. There were two in the first half of 2017 before Harvey, which the experts found “surprising” because before 2016 no more than two $1bn inland flooding events had occurred in any year since 1980.

The magnitude of the impact of a disaster is often proportional to the scale of government response required and paid for by taxpayers, said Adam Smith, a Noaa applied climatologist and the primary researcher for the analysis of $1bn disasters.

Many households lack flood insurance and are at risk of losing everything. We are seeing this on an unprecedented scale Adam Smith, Noaa

“This is particularly true for hurricane and inland flood events,” he said, “since many US households lack flood insurance and are at risk of losing everything. We are now seeing this unfold on an unprecedented scale due to Hurricane Harvey.”

Smith added: “The US has seen an increase in costly, historic flooding disasters in recent years, which is very troublesome when looking into the future. It’s unclear if Harvey’s costs will ultimately surpass Katrina. However, since this is an unprecedented extreme precipitation event over a major city, in addition to the damage to other cities and regions from wind, storm surge and flooding, it’s very possible.”

NCEI cost estimates are based on a range of public and private data sources. They take into account total direct losses incurred in weather and climate events, of both the insured and uninsured, including damage to all buildings and the assets within; the cost of business interruption; damage to vehicles, boats, offshore energy platforms and public infrastructure; and destruction of agricultural assets.

Smith cited analysis from Erwann Michel-Kerjan, a risk management expert, partner at McKinsey and former adviser to the World Bank, which concludes that the cost of catastrophic hurricanes in particular hitting the US is increasingly being borne by the federal government.

The taxpayer shouldered less than 10% of the cost of Hurricane Diane in 1955 and a quarter of the cost of Hurricane Hugo in 1989, according to Michel-Kerjan, but 50% the cost of Katrina in 2005 and 80% of the cost of Hurricane Sandy in 2012.

Noaa has been developing new methods of flood forecasting, which advocates fear will come under threat, with many other aspects of the agency’s work, if federal funding is cut.

The Noaa experts refused to comment on funding issues.

Jeff Watters, director of government relations for the nonprofit Ocean Conservancy, said: “Noaa’s research is crucial in so many aspects and its new methods of flood forecasting, for example, can be a matter of life and death.”

The Senate rejected almost all of Trump’s proposed cuts to Noaa when it reviewed his budget earlier this year. Congress resumes business next week, beginning negotiations to produce a federal budget by the end of September.

Robert Stavins, professor of energy and economic development at the Kennedy School of Government at Harvard, said: “I would hope that Noaa would continue to be a center of scientific excellence for the US government.”