Weather trends point to need for preparedness

Created on Friday, 02 December 2011 08:54

Nor’easters, tornadoes, hurricanes, earthquakes, mid-fall snowstorms, blizzards and ice storms. The past several months and years have been marked by unusual and extreme weather events in Massachusetts.

Last year’s record snowfall forced many municipalities to plow through their snow removal budgets not long after the season began. If recent history is any indication, the state could be in for another tumultuous winter.

This spate of intense weather has taken a substantial bite of municipal budgets as communities grapple with the increased costs of maintaining services during weather emergencies – overtime, for example – as well as rebuilding, cleanup and debris removal afterwards.

The question is, is this “just weather in New England”? Or are dramatic weather events getting more frequent and severe? And what does this mean for Massachusetts municipalities?

“Climate Change Indicators in the United States,” a report issued last year by the U.S. Environmental Protection Agency, presents compelling evidence that the composition of the atmosphere and many fundamental measures of climate in the United States are indeed changing. The trends indicate that we can expect severe weather events to become more frequent.

The report looks at 24 of 110 environmental indicators tracked by the EPA to understand the causes and effects of climate change. [The report is available at www.epa.gov/climatechange/indicators.html.] The following are some of the findings:

• Temperatures: Average temperatures have risen across the lower 48 U.S. states since 1901, with an increased rate of warming over the past 30 years. Parts of the North, West, and Alaska have seen temperatures increase the most. Average global temperatures show a similar warming trend, and 2000-2009 was the warmest decade on record worldwide.

This is relevant because changes in air temperature can cause changes in sea surface temperature, which affect precipitation patterns and other aspects of the climate.

• Precipitation: Worldwide precipitation from 1901 to 2008 has increased at an average rate of 2 percent per century, while average precipitation in the United States has increased at a rate of 6.4 percent per century. The average increase in New England, however, is between 10 percent and 20 percent per century.

In recent years a higher percentage of precipitation in the United States has come in the form of intense single-day events featuring above-average or heavy precipitation. Eight of the top 10 years for extreme one-day precipitation events have occurred since 1990.

The frequency of abnormally high annual precipitation totals has also increased.

• Tropical Storm Intensity: The intensity of tropical storms in the Atlantic Ocean, Caribbean, and Gulf of Mexico did not exhibit a strong long-term trend for much of the 20th century, but the intensity has risen noticeably over the past 20 years.

Six of the 10 most active hurricane seasons have occurred since the mid-1990s. This increase is closely related to variations in sea surface temperature in the tropical Atlantic. Of course when hurricanes hit land they bring intense rain, high winds and storm surges, putting populated coastal areas at risk for severe flooding and destruction.

• Ocean Surface Temperatures: Because oceans constantly interact with the atmosphere, sea surface temperatures have an affect on climate and precipitation. Warmer oceans increase the amount of water in the atmosphere. The amount of atmospheric water vapor over the world’s oceans is estimated to have increased by 5 percent during the 20th century. Even with some year-to-year variation, the overall increase is statistically significant.

Sea surface temperatures, rising at an average rate of 0.21 degrees for the past three decades, have been higher during this period than at any other time since large-scale measurement began in the late 1800s. This increased level of water vapor is the cause of increased hurricane intensity, high wind speeds, and heavier rain and snowfall.

• Rising Seas: The average sea level worldwide was increasing at a rate of roughly six-tenths of an inch per decade since 1870, but the rate has accelerated to more than one inch per decade in recent years, due in part to melting glaciers. Melting appears to have accelerated over the last decade, and glaciers worldwide have lost more than 2,000 cubic miles of water since 1960.

While climate change is a growing concern for all communities, it is of particular concern for those along increasingly populated coastlines. According to the U.S. Census Bureau and Woods & Poole Economics Inc., coastal counties account for 17 percent of land area in the U.S. (excluding Alaska), but have 53 percent of the U.S. population. Since 1980, population density in U.S. coastal communities has increased by 28 percent. In Massachusetts, coastal communities accounted for one third of the state’s total population in 2000, according to the Office of Coastal Zone Management.

As migration toward the coast continues, more people and property will be affected by increasingly volatile weather patterns. For cities and towns, this means an ever-increasing demand for services such as snow and debris removal, road maintenance, emergency response, and coastal erosion and flooding prevention and maintenance.

Severe weather events can mean school and work cancellations, dislocation of municipal employees, compromised communications with residents and staff at critical times, and impaired power and phone service. As state and federal emergency response budgets continue to shrink, Massachusetts cities and towns are being called upon to do more.

The trends make a strong argument for making municipal emergency response planning a high priority. It will be in the financial interest of communities to plan ahead in an attempt to lessen the impact of severe weather events.

By Robert Marinelli

Robert Marinelli ( This email address is being protected from spambots. You need JavaScript enabled to view it. ) is MIIA’s Risk Control Manger.

Joel Chansky, a consulting actuary with Milliman, contributed to this article.