Text and photos by Henrylito D. Tacio
The sea level is rising fast!
According to a new study published in Nature, the world’s oceans are now rising far faster than they did in the past. The current sea-level rise rate — which started in 1990 — is 2.5 times faster than it was from 1900 to 1990.
The study found that for much of the 20th century, sea level rise was about 30% less than earlier research had figured. “But that’s not good news because about 25 years ago the seas started rising faster and the acceleration in 1990 turns out to be more dramatic than previously calculated,” wrote Seth Borenstein in a dispatch for Associated Press.
“We’re seeing a significant acceleration in the past few decades,” study lead author Carling Hay, a geophysical researcher at Harvard University, was quoted as saying.
According to the report written by Borenstein, previous research showed that between 1900 and 1990, the seas rose about two-thirds of an inch a decade. The new study recalculates the 1900-1990 rate to less than half an inch a decade. Old and new research both say that since 1990s seas are rising at about 30 millimeters a decade.
“The implications are troubling — accelerated ocean warming, ice sheet collapse and sea level rise — all point to more and more sea level rise in the future, perhaps at a faster rate than previously thought,” noted Jonathan Overpeck, co-director of the Institute of the Environment at the University of Arizona. “This will make adaptation to climate change more difficult and costly.”
As a consequence of climate change, project sea-level rise is a highly difficult, complex, and controversial scientific problem, according to a report released by the Washington, D.C.-based World Bank.
Using the analysis of “semi-empirical” approach — projecting global sea-level rise by taking into account the observed relationship between past sea-level rise and global mean temperature over the past millennium — a 50 centimeter sea-level rise by the 2050s “may be locked in whatever action is taken now.”
The World Bank report — entitled Turn Down the Heat: Climate Extremes, Regional Impacts and the Case for Resilience — maintained: “Limiting warming to 2⁰C may limit sea-level rise to about 70 centimeters by 2100, but in a 4⁰C world over 100 centimeters can be expected, with sea-level rise in the tropics 10-15% higher than the global average.”
Let’s take a closer look at our region, Southeast Asia. “Due to location of the region close to the equator, sea-level rise along the South East Asian coastlines projected by the end of the 21st century relative to 1986-2005 is generally 10-15% higher than the global mean,” the World Bank report said.
While the sea-level rise near Yangoon (Burma) and Krung Thep (Bangkok) is a bit lower, for all locations in the region, the projected sea-level rise will “be considerably higher than the global mean,” with Manila at the high end.
“For these locations, regional sea-level rise is likely (more than 66% chance) to exceed 50 centimeters above 1986-2005 levels by about 2060 and 100 centimeters by 2090, both about 10 years before the global mean exceeds these levels,” the World Bank report said.
According to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), an increasing trend in the sea level in the country was observed way back in the 1965 yet.
A research conducted by the Philippine Country Study to Address Climate Change, the Manila Bay is already subjected to several hazards, including flooding and storms. “Shoreline changes due to reclamation for housing, ports, coastal roads, buildings and other urbanized development are high, adding to an increased threat of inundation,” the study said.
Let’s take Davao City as a case in point. The recent Business Risk Assessment and the Management of Climate Change Impacts, published by the World Wide Fund for Nature (WWF) and Bank of the Philippine Islands (BPI), said that sea-level rise may create problems for Davao City’s ports.
“Located along the relatively shallow channel between the city and Samal Island, these port facilities are a nerve center for Davao City’s economy, and serve a variety of ships handling both cargo and passengers,” the risk assessment said.
Sea level rise is also expected to make groundwater becomes salty in taste. “Salinity intrusion into groundwater resources occur naturally to some extent in most coastal regions via the hydraulic connection between groundwater and seawater including through canals and drainage channels,” the World Bank report said.
A United States Agency for International Development study in 2013 projects changes in salinity intrusion under a 30-centimeter sea-level during the 2045-2069 period, “which are expected to be moderate during the wet season but significantly more severe during the dry season.”
Salty water is bad for your health. “The most common consequence of excessive salt ingestion is hypertension,” the World Bank report said. “Along with hypertension, there is a broad range of health problems potentially link with increased salinity exposure through bathing, drinking, and cooking; these include miscarriage, skin disease, acute respiratory infection, and diarrheal disease.”
Salt intrusion is indeed bad news. In Davao City, for instance, the sources of water are in danger of becoming salty. “Davao has traditionally tapped surface water from its rivers as its main water source,” the WWF/BPI report said. “It prides itself in the relatively high quality of its drinking water. However, salt intrusion has already been reported in city districts to shore, especially in portions of the city where groundwater extraction continues. Sea level rise may aggravate this situation.”
Scientists claim that for every meter the sea level rises, some three kilometers of inland would be inundated. The sea will literally rise to flood the plains. “Are the people ready for such scenario?” someone asked.
Sea level rise is one of the certain outcomes of climate change. It was Dr. James E. Hansen of the US National Aeronautics and Space Administration who first raised the problem of climate change. In 1988, he told an American Senate hearing that the greenhouse effect “is changing our climate now.”
The greenhouse effect is a natural warming process. According to Dr. Perez, carbon dioxide and certain other gases are always present in the atmosphere. These gases create a warming effect that has some similarity to the warming inside a greenhouse, hence the name “greenhouse effect.”
Here’s what happens: “Visible sunlight passes through the atmosphere without being absorbed; some are back-scattered. Some of the sunlight striking the earth is absorbed and converted to heat, which warms the surface. The surface emits heat to the atmosphere, where some of it is absorbed by greenhouse gases and re-emitted toward the surface. Some of the heat is not trapped by greenhouse gases and escapes into space.”
The planet has been warming since prehistoric times, but man’s tampering with the environment has made the temperature change faster. “While human activities during the past century have damaged a long list of nature systems, most of these problems are local or regional in scope and can be reversed in years or decades if sufficient effort is exerted,” wrote Christopher Flavin in his book, Slowing Global Warming: A Worldwide Strategy.
“Changes to the earth’s atmosphere, on the other hand, are global and — for all practical purposes– irreversible not only in our lifetime but in our children’s and grandchildren’s as well,” Flavin added.
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