Sea level rise and subsidence

The formation and maintenance of shorelines, wetlands, barrier islands, estuaries and lagoons of the Gulf Coast are intimately linked with sea level. Geologic records indicate that global sea level has risen about 120 m since the Last Glacial Maximum approximately 20,000 years ago. Sea level rose rapidly (averaging almost 0.9 m per century) between 20,000 and 6000 years before present and slowed to about 0.02 m per century or less during the past 3000 years (IPCC, 2001). From the mid-19th...

Human development activities and impacts

Human development activity during the past century had more of an impact than climate change on most coastal regions (Scavia et al, 2002 Nicholls et al, 2007). The Gulf Coast region comprises some of the most valuable and heavily populated coastal landscape in North America. The total population of the coastal counties in the five Gulf Coast states has roughly doubled since 1950 and is projected to grow another 40 per cent or more by 2025, compared with an average of 23 per cent for the entire...

Reducing coastal risk

Harvey Flooded Galveston Seawall

With so many living on the coastal edge, how can society reduce the inevitable risks of living near the shore Beach nourishment is seen by an increasing number of coastal communities as an alternative to forcing people to move from the coasts, even though many replenished beaches have lasted only a few years rather than decades for most locations, this strategy cannot work in the long term. Armoring the beach with seawalls can stabilize the shore, but the monetary and aesthetic costs are very...

State of the ice sheets

Unlike the Arctic, which is an ocean surrounded by land, Antarctica is land surrounded by ocean. While both the Greenland and West Antarctic Ice Sheets are changing in similar ways, the changes do not match expectations (see Chapter 5 for a discussion of the changes currently happening in Greenland). Satellite monitoring of the West Antarctic Ice Sheet (WAIS) has revealed several changes in recent decades that seem to be responses to direct interaction with the surrounding ocean, facilitated by...

The current renewables boom

In an absolute sense, the world is heavily dependent on fossil fuels, which currently provide over 80 per cent of the energy on which global society depends. However, the annual growth rates of various energy sources show that change is on the way (see Figure 19.1). Since 2001, the growth rates of the solar photovoltaic (30 per cent), wind (26 per cent) and biofuel (17 per cent) sectors have been much larger than for the traditional sectors of coal (4.4 per cent), oil (1.6 per cent), natural...