How will climate change affect water and wastewater infrastructure planning, design, and construction?
Pamela Wolfe, Managing Editor
Rising global temperatures, sea levels, and intensifying hurricanes are phenomena caused by the burning of fossil fuels and human activities, according to the new Intergovernmental Panel on Climate Change (IPCC) report published on February 2, 2007, which makes this claim with 90 percent certainty.
The majority of scientists around the world have shared this conclusion after reviewing the vast amount of research that has been carried out and verified within the past few years. However, the IPCC report, which is the most comprehensive and authoritative scientific report on climate change carried out so far, provides an unequivocal message to political leaders who have previously disregarded the effect of burning fossil fuels on climate change.
Twelve hundred climate experts from 40 countries contributed to the report, completed under the auspices of the United Nations Environment Programme and the World Meteorology Organization.
How will climate change affect water and wastewater infrastructure? Professionals attending water-related conferences in Africa, Asia, Australia, Europe, and the Americas have been increasingly concerned with the challenges created by changing weather patterns - and are grappling with questions of how to cope with the effects.
Long, severe droughts are diminishing water supply resources for major cities in Australia, driving governments to invest in desalination plants. More frequent, intense rainfall events in Central Europe are overloading treatment plants, flooding river valleys that destroy lives and property. Coastal hurricanes and storms with winds of 150+ miles per hour cause great damage from ocean surges in low-lying regions. During the Katrina hurricane in September 2005, an ocean surge of 30-feet-deep reached more than one mile inland into the US state of Mississippi on the Gulf coast, destroying homes, businesses, and infrastructure. In Bangladesh, a low-lying nation with the majority of its population living in a river delta, millions of subsistence-level farmers face enormous problems from flooding.
The IPCC report says that global temperatures could most likely rise by 1.8 degrees Celsius to 4 degrees Celsius by 2100 if fossil fuels are burned at current rates. Sea level rises, therefore, could reach 18 cm to 59 cm, but this part of the report has generated much controversy as recent research indicates that glacier melting could push sea levels up to 140 cm. Water expands as temperature rise, causing sea levels to rise.
These findings are prompting many in the sector to consider the effects of climate change on coastal infrastructure, such as desalination plants, stormwater systems, and water and wastewater treatment facilities. Together, rising sea levels and intensifying storms can create significantly more dangerous and destructive seawater surges that reach farther inland. How can water and wastewater infrastructure be protected against coastal surges? Should governments not support coastal development?
Water scarcity crises already affect more than half of the world’s population. Many coastal regions in the Middle East, North Africa, North America, Caribbean, and even South Asia, now have desalination plants that were constructed to meet growing demands for drinking and industrial water supply. Perhaps a more realistic approach would be to promote strategies to mitigate and prevent damage to existing communities and developments from future coastal floods.
According to Dr. John Church, a oceanographer with the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and sea-level rise scientist with the Antarctic Climate & Ecosystems CRC, about half of Australia’s population lives within seven kilometers of the coast. Thirty percent of the population lives within two kilometers of the coast. “As more Australians move to the coast in search of a lifestyle ‘sea change,’ planning for a changing climate, including sea-level rise, is a mainstream issue in need of informed consideration,” he explained.
Dr. Church claims that Australians are beginning to recognize that climate science is presenting them with outcomes and suggesting options for adaptation. Appropriate strategies and investment in coastal adaptation, if implemented early enough, can dramatically reduce the potential for economic loss and human tragedy during the 21st century, he said.
These strategies include: planning for future flooding events; developing set-backs for regions susceptible to flooding and erosion; and protection measures, such as sea walls in some locations; and retreat or abandonment of other facilities in flood-prone areas.
The only options for some Pacific and Asian rim nations, however, are internal or external relocation, Dr. Church added.