Osmeña: Why worry about climate change?

THERE is vigorous debate among climatologists over how the over-all global climate might change and to what degree human activities might influence these changes.

Climate experts have made three general projections about climate change in the next few decades: 1) we can’t tell what will happen; 2) it will get colder because of the long-term natural trends in global climate or a combination of natural trends and human activities; and 3) it will get warmer over the next century primarily because of human activities that counteract the natural and human-caused cooling trends.

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What then can be done? Suggestions to prevent the problem from reaching crisis levels include 1) not shifting to coal, shale oil, or synfuels as a major energy source over the next 50 years and relying more on a combination of energy conservation and increased use of renewable energy resources, like the sun, wind, flowing water, 2) using scrubbers to remove carbon dioxide from the stack of coal-burning power and industrial plants – a technically feasible but expensive solution, planting more trees to reduce the greenhouse effect by increasing the uptake of carbon dioxide from the atmosphere as well as reducing harmful effects of deforestation, and 3) reducing soil erosion, which releases carbon dioxide.

Is heat the ultimate pollutant? Take a breath, raise your arm, turn on a light, drive a car, or air-condition your house or car, and you add heat to the atmosphere.

According to the second law of energy, whenever energy is used, some of it is degraded to infrared heat, which flows into the atmosphere and is eventually radiated back into space.

If human activities in an area produce energy faster than it can be radiated back into space, the average temperature in that area will rise – just as an auditorium heats up when it is filled with people, each one giving off heat equivalent to that emitted by a 100-watt bulb.

This heating is already occurring in large cities and urban areas. Anyone who lives or works in a city knows that it is typically warmer there than in nearby suburbs or rural areas. Day in and day out, cities emit vast quantities of heat.

Absorbing heat

Concrete buildings and asphalt pavement absorb heat during the day and release it slowly at night. Tall, closely spaced building slow wind velocity near the ground and reduce the rate of heat loss.

Water rapidly runs off the paved surfaces in cities, in contrast with rural areas, where water soaks into the soil and then slowly evaporates to cool the surrounding air.

Thus, it is not surprising that a dome of heat hovers over a city, creating what is called an urban heat island. Not only is a city warmer than rural areas, but is typically has lower visibility, more air pollution, less wind, and lower humidity.

In the early 1950s, the area within the town proper of Talisay about 20 kilometers from Cebu City had water flowing freely out of the well without pumping. Such wells are called artesian wells. The hydraulic pressure within the confined aquifer was so great that water flowed freely.

Today, you need to drill 200 meters deep with a pump to produce water due to failure of rain water to percolate and replenish the aquifer. The lack of political will to stop the rampant deforestation of Talisay’s hinterland failed to recharge the aquifer thru precipitation.

Then, Mactan Island’s pristine coastlines used to have a vast population of phytoplankton, the floating plants that are the grass of the sea. These plants support the zooplankton and bottom-feeding invertebrates where sea horses also abound.

Unfortunately, the projected change in average global temperature could modify the distribution of rainfall and increase temperature of water along the coastlines. Where more and more people try to use the shoreline resources, increasing stress is placed along the estuarine zone.

Today, Cebu and its neighboring islands are at a critical turning point. The prospect for our inhabitants is both brighter and darker than at any time in history.

Prophets of doom warn that the earth’s life-support systems are being destroyed, and technological optimists promise a life of abundance for everyone. We must learn the importance of protecting the diversity of life on the beautiful blue planet that is our home.

The problems associated with increasing population, increasing use of resources, and population are all related and could even be worse than worrying about climate change.