Planning For Future Weather Extremes In New Jersey

Anthony J. BroccoliDirector, Climate and Environmental Change Initiative

Department of Environmental SciencesRutgers University

New Jersey Future Redevelopment ConferenceNew Brunswick, NJ

March 1, 2013

Recent extreme weather events

“Boxing Day Snowstorm” (Dec. 26-27, 2010)

Hurricane

Irene

October 2011 Snowstorm June 2012 Derecho

Hurricane/Superstorm Sandy

Sandy All previous tropical systems passing

within 50 miles of Atlantic City

Storm surge from Sandy

Three questions…

• What do we mean by “normal” climate?

• Is there a “new normal,” in which Sandy and other recent extremes are harbingers of future events?

• How can we prepare for future weather and climate impacts?

What do we mean by “normal” climate?

• We use the term “normal” to describe the expected range of conditions, including averages and extremes, at a location.

• This definition of normal arises from the concept of stationarity.

• Stationarity is the assumption that the future will be similar to the past, in a statistical sense, and that we can estimate the probability of future events (for example, a “100-year storm”) from past records.

• Even in a stationary climate, weather events that are more extreme than those on record can happen, because modern weather records only extend back in time for a limited period.

Is there a new normal?

Climate Change 101: The Basics

• Combustion of fossil fuels (coal, petroleum, natural gas) emits carbon dioxide into the atmosphere (currently about 9 billion tons of carbon per year).

• Slightly less than half of the carbon dioxide remains in the atmosphere; most of the remainder goes into the ocean (causing ocean acidification).

• Increasing carbon dioxide heats the earth; global temperatures have risen by 1.5-2°F during the past century.

• Increasing temperatures also cause other changes in climate and sea level.

What the science says…

• We do not know if hurricane activity (i.e., intensity, frequency, duration) has changed systematically in the past. In the future, hurricanes will probably increase in strength but their number will either decrease or remain essentially unchanged.

• We do not know if severe thunderstorms and tornadoes have become more frequent (because observational methods have improved) and future trends are uncertain.

• Many areas have experienced upward trends in the number of heavy precipitation events and it is likely that such trends will continue throughout the 21st century.

• Record high temperatures and heat waves have been occurring more frequently and they are expected to increase further during the 21st

century.

• The ongoing rise in sea level has raised the baseline for coastal flooding from storm surge and the rate of sea level rise will likely accelerate during the remainder of the 21st century.

Sea level trends along NJ coast

16 inches in 100 years

Projection for 2050: 9-24” (best estimate of 16”)

Projection for 2100: 20-58” (best estimate of 38”)[Source: R. Kopp and K. Miller, Rutgers University]

Historic water levels at Sandy Hook

• >13.2 FT — October 29, 2012 (Sandy)

• 10.1 FT — September 12, 1960 (Hurricane Donna) / December 11, 1992.

• 9.8 FT — August 28, 2011 (Hurricane Irene).

• 9.7 FT — November 7, 1953.

• 9.4 FT — September 14, 1944 (Hurricane) / March 6, 1962.

• 9.0 FT — November 25, 1950.

• 8.9 FT — January 23, 1966.

• 8.8 FT — November 12, 1968.

• 8.7 FT — MAJOR TIDAL FLOODING BEGINS.

• March 29, 1984 / March 13, 1993.

• 8.6 FT — September 27, 1985 (Hurricane Gloria) / January 2, 1987 / October 31, 1991.

• 8.5 FT — April 13, 1961.

• 8.3 FT — February 19, 1972 / March 19, 1996 / March 13, 2010.

• 8.2 FT — October 18, 2009.

• 8.1 FT — January 31, 2006 / April 16, 2007.

• 8.0 FT — October 14, 1955 / December 26, 1969 / December 2, 1974 / April 16, 2011.

• 7.9 FT — August 31, 1954 (Hurricane Carol) / December 22, 1972 / October 25, 1980 / February 24, 1998 / December 25, 2002 / November 14, 2009.

• 7.8 FT — October 14, 1977 / November 8, 1977 / March 3, 1994 / December 20, 1995 / January 29, 1998 / March 30, 2010.

• 7.7 FT — MODERATE TIDAL FLOODING BEGINS.

• March 20, 1958 / October 22, 1961 / November 10, 1962 / December 25, 1978 / December 3, 1986 / January 4, 1994 / December 13, 1996 / November 14, 1997 / January 3, 2003 / January 3, 2006 / February 12, 2006 / October 7, 2006 / May 12, 2008 / December 12, 2008 / May 17, 2011.

• 6.7 FT — MINOR TIDAL FLOODING BEGINS

The future will not be the same as the past

• “We never had floods like this before. We made preparations but it didn’t do any good…”

• “There was no reason for us to think that the kind of flooding that we actually experienced would happen there.”

• “We had flooding in areas we never had flooding before.”

• “...we've never had flooding before…The house has been in the family since it was built in 1964 and there's never been a problem with weather...ever.”

• “They thought they'd be safe because they'd never had flooding before.”

How can we prepare for future weather and climate impacts?

• Recognize that the past is not an adequate guide to what will happen in the future (limited records, changing climate).

• Use information from climate model projections, with careful interpretation, to develop an understanding of the effects of a changing climate baseline.

• Focus on aspects of climate change that we understand with high confidence (such as sea level rise) rather than those that are more uncertain (such as changes in storm frequency/intensity).

• Develop improved methods for making projections of the effects of climate change on high impact weather events.