Will rains increase as global air pollution reduces?

A new research from the United Kingdom's National Weather Service, the Met Office investigates why there has been no increase in global average rainfall over land during the last century despite a 0.8°C rise in average temperatures on the planet.

As they explain, the hydrological cycle is a key component of the Earth's climate system. Changes in this cycle have a direct impact on droughts, floods, water resources and ecosystems. Increasing levels of greenhouse gases, contributing to the warming of the planet, would be expected to increase the hydrological cycle, but that isn't what was observed.

In their studies, Met Office scientists found evidence that man-made industrial air pollutants had a significant impact on rain patterns. The sun heats the Earth, causing warm air to rise through cooler air above, which condenses the moisture in the air and produces rain. Greenhouse gases increase temperatures at the planet's surface and higher up in the atmosphere, which leads logically to thinking that rainfall would increase due to the extra heat in the system. However, researchers have found that industrial pollutants make clouds brighter, causing them to reflect more energy from the sun back into space, which in turn means less heat is getting to the Earth's surface. This affects the hydrological cycle with evaporation and therefore means less rain, the Met Office report shows.

In tropical Costa Rica, residents are grateful that seasonal rains started in May – even if it is raining sporadically and not regularly every afternoon uniformly across the country. It may seem impossible that a tropical country covered in rainforest can experience drought, but it can. An unusually dry rainy season in 2012 left the country's aquifers dry, affecting some 20,000 residents along with plants and animals with drastic water rationing. The areas of Heredia and Cartago in the Central Valley, and most of Guanacaste in the Northern Pacific were most affected.

If you are planning or thinking to travel to Costa Rica, you'll be happy to know that there has been enough rain to transform the landscape into lush greenness with bursts of bright flowers everywhere. And at the same time, there is still plenty of sunshine to let you enjoy all of your adventures. Costa Rica travel agency Team CRT creates unforgettable Costa Rica vacation itineraries and packages. Team CRT arranges nature tours, beach vacations, adventure tours, family vacations, relaxation vacations, honeymoons and golf vacations.

By Shannon Farley