Climate Change Data: Stories for Action from Global to Local Scale

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At McKinsey’s Global Sustainability Summit in Chicago in mid-May, the consulting giant’s clients from around the world met to discuss sustainability “at a tipping point.” The theme signals the mounting concerns its clients are expressing as they grapple with the physical impacts of climate change and seek new opportunities for sustainable growth and innovation.

For corporate leaders, a major theme was, “make the risks of climate change actionable,’ in part through story lines that move through various geographic scales and feature the impact of climate risk projections on economies. In the U.S., we benefit from a comprehensive National Climate Assessment that lets us do just that.

Global Sea Level Rise

The U.S. Interagency Sea Level Rise Task Force provides six scenarios for assessing global mean sea level (GMSL) that could affect local communities (image a). The low scenario of 30 cm (about 1 foot) GMSL rise by 2100 is consistent with the current rise rate of 3 mm/year (0.12 inches/year).

The highest scenario of 250 cm mirrors several estimates of the maximum physically plausible level of sea level rise in the 21st century. It also is consistent with the high end of recent projections of Antarctic ice sheet melt. These scenarios are used for risk framing. According to the National Oceanic and Atmospheric Administration, almost 40 percent of the U.S. population live in relatively high-population-density coastal areas, where global sea level plays a role in flooding, shoreline erosion and hazards from storms.

Because the sea surface is not changing at the same rate at all points around the globe, sea level rise at specific locations may be more or less than the global average due to many local factors (image b).

Local Sea Level Rise

Beyond global sea level trends, sea level rise risks are identifiable for cities around the U.S. Using NOAA’s Coastal Flood Exposure Mapper, it is possible to  examine multiple flood hazards with high resolution models that incorporate potential sea level rise impacts, such as that for Charleston, S.C. (image c)

Sea Level Rise Effects on Economy

Besides impairing coastal infrastructure, regional/local sea level rise also effects local economies. For instance, by 2045, Charleston is projected to experience up to 180 flood events a year that cause delays in vehicular traffic. City officials estimate that each flood event affecting the main traffic artery costs $12.4 million (in 2009 dollars). Over the past 50 years, the damage and lost wages from delayed traffic have totaled more than $1.53 billion. More broadly, on the U.S. East Coast, over 7,500 miles of roadway are located in high tide flooding zones. Unmitigated, this flooding has the potential to nearly double the current 100 million vehicle-hours of delay likely by 2020 (image d).

Cities are taking action on this data. For instance, Charleston has developed a Sea Level Rise Strategy that plans for 50 years out. It reflects moderate sea level rise scenarios and reinvestment in infrastructure, development of a response plan, and increased readiness. As of 2016, the City of Charleston had spent or set aside $235 million (in 2015 dollars) to complete ongoing drainage improvement projects to prevent current and future flooding.

Corporations can too.

Thank you to Baylee Ritter for co-athoring and to Allyza Lustig, U.S. Global Change Research Program (USGCRP) for her help with information.