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Sea Level Rise

What is Expected for New York

aerial view of Long Island
Rising seas and increased storm surges
put New York's coastlines at risk.

Fast Facts - Sea-level Rise in New York

  • New York has an estimated 1,850 miles of tidal shoreline exposed to the action of tides, wind and waves - much of it developed and densely populated.

  • New York has experienced at least a foot of sea-level rise since 1900, mostly due to expansion of warming ocean water. Certain conditions along New York's coast make sea-level rise here somewhat higher than the global average.

  • New York's coastal marine counties already see more intense storm surges and floods. Superstorm Sandy highlighted the risks and vulnerabilities of our tidal shorelines, which are home to more than half of New Yorkers.

  • By 2100, scientists project sea levels 18 to 50 inches higher than today along New York's coastlines and estuaries, though a rise as high as 75 inches could occur.

  • Sea-level rise is locked in for centuries, or even millennia, by heat-trapping greenhouse gases already in the atmosphere. Continuing or increasing emissions will speed up the rise to higher levels.

  • Energy, land use and infrastructure decisions made now will determine how vulnerable our children and grandchildren will be to rising sea-levels.

Assessing risks and planning for resilience

Sea-level rise poses a significant risk to New York's people, resources and economy. Especially when levels are rising rapidly, communities and individuals need science-based projections to evaluate risks and plan for adaptation.

Currently, the best available projections for planning purposes are found in the 2014 Supplement to ClimAID (ClimAID link at right). Under the recently-adopted CRRA statute, New York will establish official State sea-level rise projections by early 2016.

Community Risk and Resiliency Act (CRRA)

The Community Risk and Resiliency Act (CRRA) designates specific State permitting, facility siting and funding programs that must take into account the intensified impacts of storm surges and floods as sea-levels rise. To facilitate impact evaluation, the law directs DEC to adopt science-based sea-level rise projections by January 1, 2016 and to provide guidance to help State agencies apply these projections.

ClimAID: 2011 and 2014

In 2011, Responding to Climate Change in New York State (ClimAID) provided the first projections of sea-level rise specifically along New York's coastlines and estuaries. The ClimAID 2014 Supplement refined these projections to take into account all known components of sea-level rise, based on advances in physical understanding, climate modeling and computing and reflecting observational data that include Hurricane Irene and Superstorm Sandy. DEC considers these projections to be the best available at this time for New York planners.

Sea-level Rise Task Force

In a report issued early in 2011, the New York State Sea Level Rise Task Force assessed sea-level rise impacts and identified the greatest threats to coastal communities and natural resources:

  • Increased frequency and intensity of severe flooding and storm surge damage, not only to communities and infrastructure, but also to critical ecosystems that buffer against floods, protect drinking water and provide habitat for important species;
  • Increased erosion of beaches and bluffs;
  • Inundation of low-lying areas;
  • Saltwater infiltration of surface waters and aquifers;
  • Possible compromise of low-lying sewage, wastewater, transportation, communication, and energy infrastructure and systems.

Sea Level Rise Task Force recommendations are the basis for many of New York's current climate change adaptation policies.

Projected sea-level rise in New York

Sea-level rise projections adopted for New York State will draw on previous expert projections, with the benefit of input from participants in a series of public meetings held in June, 2015.

Global sea-level rise

Since 1900, global mean sea-level rose by about 8 inches; since the mid-19th century the rate of sea-level rise has been larger than the mean rate during the previous two millennia, according to the Summary for Policymakers of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, prepared by collaboration of hundreds of climate scientists around the world under the auspices of the United Nations. If moderate amounts of land ice melt, the IPCC projects the likely global sea level rise by 2100 will be approximately 20 to 38 inches, estimating that a rise of that magnitude will be experienced by 70 percent of the world's coastlines.

New York State sea-level rise

Certain regional conditions, such as subsidence of coastal lands, make it likely that sea-level rise in New York will exceed the global mean. Tide-gauge observations indicate that rates of relative sea-level rise in New York State over the last century have been greater than the global mean, averaging 1.2 inches per decade.

[The term relative sea level means the height of the sea relative to a land benchmark. Relative sea level takes into account both global sea level and certain local factors, including subsidence or uplift of the earth's crust in response to groundwater or mineral extraction, changes in glaciation, tectonic activity, sediment consolidation or short-term climatic fluctuations (e.g., El Nino Southern Oscillation). These regional components are described in the 2014 ClimAID Supplement.]

2014 ClimAID Supplement Sea-Level Rise Projections

Montauk Point

Baseline (2000-2004) 0 inches Low Estimate (10th Percentile) Middle Range (25th to 75th Percentile) High Estimate (90th Percentile)
2020s 2 in 4 to 8 in 10 in
2050s 8 in 11 to 21 in 30 in
2080s 13 in 18 to 39 in 58 in
2100 15 in 21 to 47 in

72 in

New York City

Baseline (2000-2004) 0 inches Low Estimate (10th Percentile) Middle Range (25th to 75th Percentile) High Estimate (90th Percentile)
2020s 2 in 4 to 8 in 10 in
2050s 8 in 11 to 21 in 30 in
2080s 13 in 18 to 39 in 58 in
2100 15 in 22 to 50 in

72 in

Troy Dam

Baseline (2000-2004) 0 inches Low Estimate (10th Percentile) Middle Range (25th to 75th Percentile) High Estimate (90th Percentile)
2020s 1 in 3 to 7 in 9 in
2050s 5 in 9 to 19 in 27 in
2080s 10 in 14 to 36 in 54 in
2100 11 in 18 to 46 in

71 in

The timeslices in the table refer to decades. For example, the 2020s timeslice means the period 2020-2029. Model results are expressed as outcomes or ranges of outcomes at different levels of probability. For example, if 90 percent of the model results occurred below the 90th percentile level, there would be a less than ten percent likelihood of the sea rising by more than that amount. Expressing outcomes in this manner helps decisionmakers assess risks by making it easier for them to take into account both the probability of an event and the severity of the event's consequences.

The technical basis for New York sea-level rise projections given here is found in the report of the Sea Level Rise Task Force and the ClimAid Integrated Assessment for Effective Climate-change Adaptation Strategies in New York State.

It is important to remember that sea-level rise will continue for centuries beyond 2100, so that for many decisions it is not a matter of whether a certain sea-level rise will occur, but when.


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