Climate change dominates public policy despite myths and rumors

limate is the driving force in public policy, and Costa Rica is among the leaders. Yet facts often give way to rumors and myths.

Today is the last day of an environmental fair at the Antigua Aduana on Calle 23, and climate change, air pollution and related topics were the themes.

A Costa Rican housing agency tried to put out regulations last month that would have prevented a lot of development in the lands outside the core cities. San José officials are promoting repopulation, a plan to bring more residents back to the metro center to reduce commuting time, vehicle use and pollution.

Costa Rica supports the Intergovernmental Panel on Climate Change and United Nations efforts to reduce the emissions of carbon dioxide, a so-called greenhouse gas, into the atmosphere.

Officials here seem to agree wholeheartedly that humans are one of the principal causes of rising world temperatures. The antidote is to restrict some human activities.

A news story Thursday about a photo exhibit at the Aquarium of the Pacific quoted director Jerry Schubel saying “Global climate change is resulting in rising seas, coastal flooding and increasingly powerful storm surges.”  Some readers objected, and one said that the global temperature has not risen for 18 years.

Schubel, an eminent oceanographer with many years standing, certainly must know that the sea has been rising for the last 18,000 years since the end of the Ice Age. What he probably also said that did not make the story is that sea level rise is accelerating.

The rise is attributed to expansion due to rising water temperature and glacial runoff. Since the end of the Ice Age, the oceans have risen about 120 meters (390 feet).

And despite the comment from the reader, warming does not appear to be slowing, according to the U.S.  National Oceanic and Atmospheric Administration.

A new study published online Thursday in the journal Science finds that the rate of global warming during the last 15 years has been as fast as or faster than that seen during the latter half of the 20th Century. The study counters the notion that there has been a slowdown or hiatus in the rate of global warming in recent years, as mentioned by the reader.

The researchers used the latest global surface temperature data.

The apparent observed slowing or decrease in the upward rate of global surface temperature warming has been nicknamed the hiatus. The Intergovernmental Panel concluded that the upward global surface temperature trend from 1998­­ to 2012 was markedly lower than the trend from 1951 to 2012.

National Oceanic and Atmospheric Administration scientists said Thursday that they have made significant improvements in the calculation of trends and now use a global temperaturetrencs060515surface temperature record that includes the most recent two years of data, 2013 and 2014, the hottest year on record. The calculations also use improved versions of both sea surface temperature and land surface air temperature data sets. One of the most substantial improvements is a correction that accounts for the difference in data collected from buoys and ship-based data, they said.

Sea level height used to be measured by local tidal gauges. For the last 13 years  satellites have been used. There still are some difficulties. Sea level height is supposed to be the mean height between high and low tide. That changes with location. In fact, some spots show a decline in seal level.

And El Niño pushes large quantities of water across the Pacific to confound the measurements.

Records and research show that sea level has been steadily rising at a rate of 0.04 to 0.1 inches per year since 1900, said the National Oceanic and Atmospheric Administration.

Since 1992, new methods of satellite altimetry (the measurement of elevation or altitude) indicate a rate of rise of 0.12 inches per year. the agency said.

For the period between 1870 and 2004, global average sea levels are estimated to have risen a total of 195 millimeters (nearly eight inches). If this acceleration would stay constant, the 1990 to 2100 sea level rise would range from 280 to 340 millimeters, some 13.5 inches, according to the Weather Underground, A.M. Costa Rica’s meteorological service.

The University of Colorado predicts a higher rate. Sea level rose 85 millimeters between 1993 and 2015, says that institution. That would be 3 and 11/32nds of an inch.

During the last Ice Age, global temperatures are estimated to be from 4 to 7 degrees C colder than now, and 3 million years ago, some researchers estimate that the world was 3 degrees C warmers and the sea levels were perhaps as much as 35 meters higher, some 115 feet.

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