Since 1971 climatologists have used continuous satellite (1) technology to track and measure tropical storms. This technology has provided extensive knowledge on tropical storms, revealing that hurricanes are the deadliest and most costly type of weather related disaster (2). Accounting for more than 242 000 thousand deaths within the past 21 years (3), the largest hurricane prior to August 2017 was Katrina, costing $160 billion in 2005 and Sandy costing 70 billion in 2012 (4). Cyclonic intensity and the damages wreaked from extreme winds and mass flooding have cost people their lives, homes and businesses, causing major strains on whole countries’ economies.
August 25th, 2017 marked record breaking winds and rainfall in Texas as Hurricane Harvey touched down. According to Accuweather, this storm will likely cost the economy $190 billion (5), more than Katrina and Sandy combined. To add to the shock, just as Harvey’s damages were being assessed, Hurricane Irma came tearing through Florida and Hurricane Maria slammed Puerto Rico, resulting in similar social and economic costs. The notable escalation of tropical storm intensity thus leaves us wondering when and where the next storm will hit.
This year the U.S. has experienced, for the first time in history, three Category 4/5 hurricanes to hit land in the same year, wreaking havoc in Texas, Florida and Puerto Rico. Devastating thousands of lives, ruining billions (6) of dollars' worth of property, whilst setting back U.S economic growth by a 1% this quarter (7), according to economist Diane Swonk of DS Economics. Harvey's damages were still being estimated whilst the terror of Irma's winds gusted through Florida.
The impacts of these hurricanes are still being estimated, but are likely to set record highs for marginal damage ever endured from tropical storms. Irma's Category 5 winds of 185 mph were maintained for a record breaking 37 hours and Harvey's dumping of nearly 51 inches of rainfall left areas throughout Texas in sustained states of emergency (8).
With warming global temperatures, comes record breaking rainfall in mid-latitude regions, and massive economic and personal damages to society. This intensifying rainfall and increasing cyclonic energy is a critical outcome of climate change (9), a fact mutually agreed upon throughout the scientific community (10). What causes the intensification of rainfall in mid-latitude regions? Research tells us that the build up of sea surface heat coupled with increasing air temperatures is evidence that storms are becoming better at absorbing water vapour from the ocean, which is then absorbed into the atmosphere and later released as rain (11).
"Everything in the atmosphere now is impacted by the fact that it's warmer than it's ever been," "There's more water vapor in the atmosphere. The ocean is warmer. And all of that really only pushes the impact in one direction, and that is worse: higher surge in storms, higher rainfall in storms." said CNN senior meteorologist Brandon Miller (12).
Climate change is attributed to the increased levels of atmospheric carbon dioxide accumulated from human’s consumption of fossil fuels, which have been increasing since the second industrial revolution in the 20th century (13). The elements of climate change that are driving severe cyclonic activity include increased atmospheric and oceanic temperatures which are a consequence of human consumption of fossil fuels and emissions of greenhouse gases (GHG's) such as carbon dioxide. (14)
The mere magnitude of these storms is cause for serious concern, and scientists (15) around the world have been attributing Harvey, Irma and Maria to the changes in our planet's atmospheric composition. It is historically evident that the intensity of tropical storms is on the rise, and according to the total annual Accumulated Cyclone Energy (ACE) (16) index, the world has seen a noticeable increase in cyclone intensity over the past 20 years. Additionally, the Power Dissipation Index (PDI) (17) points to noticeable increases in cyclone intensities, coupled with major increases in sea surface temperatures since 1995. From this data it is evident that climate change coupled with increasing sea temperatures has a positive influence on cyclonic intensities. And although climate change is not the cause of these tropical storms, it has definitely increased their destructiveness over time.
Thus, "Climate change makes these very bad storms worse" according to Sean Sublette, a meteorologist with Climate Central. (18)
Furthermore, the various challenges and damages to human populations as a result of severe hurricanes is not necessarily a factor of the hurricane's strength, but a factor of the populations density, their economic welfare, and their levels of preparedness for such an event. It is true that hurricanes differ in intensities, but it is also true that they have varied paths of destruction, and the toll in which a hurricane of any kind will have on humanity is dependent on if it hits a densely populated region or not. For instance, hurricane Sandy was a Category 4 hurricane costing roughly $70 billion (19), but if Sandy were to have changed courses and touched down in a region less developed and populated than New York City, the economic, social, and human costs would have been significantly reduced.
The significant economic costs incurred by a population after a hurricane hits can include but are not limited to; disruptions in business, unemployment, transportation and infrastructure damage, massive crop loss, increased prices of oil, and major personal impairments. "Some of the losses will be covered by insurance, some will not, so the losses will be felt in a variety of ways by millions of people." (20) according to Dr. Joel N. Myers, AccuWeather founder, president and chairman. Therefore, just as higher temperatures result in higher cyclonic intensities, the larger a country's GDP the greater the socio-economic costs a hurricane such as Harvey will cause. So, with masses of people living in the Hurricane Valley, how can societies mitigate the impact of tropical storms on their socio-economic well-being?
Science has yet to come up with the technology to completely dissipate or deter a hurricane's path, however science has determined a series of factors which are directly linked to the increasing cyclonic intensities (21). As mentioned, cyclonic intensities have been on the rise since the 20th century (22) and the source of this problem is closer to home than one would like to believe. Reality hits when the world realizes that it is human emissions of GHG's which lead to stronger and longer tropical storms. So, due to the fact that we cannot stop these storms from happening, we must effectively reduce the variables which are lending to their destructiveness. Thus, populations around the world need to make conscious efforts to reduce their emissions to halt the intensification of tropical storms.
(1) US Department of Commerce, NOAA, National Weather Service. "CPHC Climatology." Pacific Region Headquarters. November 07, 2004. Accessed October 03, 2017.
(2) Guha-Sapir, Debarati. "The Human Costs of Weather Related Natural Disasters." Edited by Margareta Wahlstrom. Center for Research on Epidemiology of Distasters CRED , 2015, 5-16. 2015.
(3) Guha-Sapir, Debarati. "The Human Costs of Weather Related Natural Disasters." Edited by Margareta Wahlstrom. Center for Research on Epidemiology of Distasters CRED , 2015, 5-16. 2015.
(4) Rachael Dottle, "Hurricane Harvey’s Impact - And How It Compares To Other Storms," FiveThirtyEight, September 02, 2017, , accessed October 03, 2017
(5) "AccuWeather predicts economic cost of Harvey, Irma to be $290 billion," Local Weather from AccuWeather.com - Superior Accuracy™, September 11, 2017, , accessed October 03, 2017
(6) Riquier, Andrea. "Hurricane Harvey could cost billions in property damage - and that's not even including the flooding." MarketWatch. August 26, 2017. Accessed October 03, 2017.
(7) Javier E. David, "Hurricane Harvey probably shaved 1% from third-quarter growth, Goldman Sachs says," CNBC, September 10, 2017, , accessed October 03, 2017
(8) Andrews, Travis M. "Trump declares emergency for Louisiana as the state braces for possible Harvey-related flooding." The Washington Post. August 28, 2017. Accessed October 03, 2017.
(9) "The Rising Cost of Natural Hazards : Feature Articles," NASA, , accessed October 03, 2017, https://earthobservatory.nasa.gov/Features/RisingCost/rising_cost5.php.
(10) Welch , Craig. "How Climate Change Likely Heightened Harvey's Fury." National Geographic. September 20, 2017. Accessed October 03, 2017.
(11) Drye, Willie. "Harvey May Become the Rainiest Storm in U.S. History-Here's Why." National Geographic. August 27, 2017. Accessed October 03, 2017. http://news.nationalgeographic.com/2017/08/hurricane-harvey-floods-historic-rainfall/.
(12) Wayne Drash, "Yes, climate change made Harvey and Irma worse," CNN, September 19, 2017, , accessed October 03, 2017
(13) The Editors of Encyclopædia Britannica. "Industrial Revolution." Encyclopædia Britannica. May 02, 2017. Accessed October 03, 2017.
(14) OECD Statistics Directorate, OECD Glossary of Statistical Terms - Carbon dioxide (CO2) Definition, September 25, 2001, , accessed October 03, 2017
(15) Welch , Craig. "How Climate Change Likely Heightened Harvey's Fury." National Geographic. September 20, 2017. Accessed October 03, 2017.
(16) "Climate Change Indicators: Tropical Cyclone Activity," EPA, December 17, 2016, , accessed October 03, 2017
(17) "Climate Change Indicators: Tropical Cyclone Activity," EPA, December 17, 2016, , accessed October 03, 2017
(18) "A Science and News Organization," Climate Central, , accessed October 03, 2017
(19) Rachael Dottle, "Hurricane Harvey’s Impact - And How It Compares To Other Storms," FiveThirtyEight, September 02, 2017, , accessed October 03, 2017,
(20) "AccuWeather predicts economic cost of Harvey, Irma to be $290 billion," Local Weather from AccuWeather.com - Superior Accuracy™, September 11, 2017, , accessed October 03, 2017
(21) "Climate Change Indicators: Tropical Cyclone Activity," EPA, December 17, 2016, , accessed October 03, 2017
(22) "How Do We Know that Humans Are the Major Cause of Global Warming?" Union of Concerned Scientists, , accessed October 03, 2017
Figure 1: CENTRE FOR RESEARCH ON THE EPIDEMIOLOGY OF DISASTERS – CRED and UNITED NATIONS OFFICE FOR DISASTER RISK REDUCTION (UNISDR) (2015) The human cost of weather related disasters: 1995-2015. CRED: Brussels .