Humans change the world! What drought are you talking about? A drought is a period of unusually persistent dry weather that persists long enough to cause serious problems such as crop damage and or water supply shortages. The severity depends upon the degree of moisture deficiency, the duration, and the size of the affected area.

The major effects of climate change on water systems take place through changes in the hydrological cycle, basically the balance between temperature and rainfall. Whilst some regions may have higher rainfalls this can evaporate through sustained increases in temperature. The El Niño is strongly linked to droughts, and is a disruption of the ocean-atmosphere system in the Tropical Pacific which has important consequences for weather and climate around the globe.

Global Warming, in brief, is the warming of the Earth. Our planet, Earth, is continually being warmed by different sources. Carbon dioxide and other gases warm the surface of the planet naturally by trapping solar heat in the atmosphere. By burning fossil fuels such as coal, gas and oil and clearing forests we have dramatically increased the amount of carbon dioxide in the Earth’s atmosphere and temperatures are rising.

The vast majority of scientists agree that global warming is real, it’s already happening and that it is the result of our activities and not a natural occurrence. The evidence is overwhelming and undeniable. We’re already seeing changes. Glaciers are melting, plants and animals are being forced from their habitat, and the number of severe storms and droughts is increasing.

Average global temperatures have risen every decade since the 1970s. 2010 tied 2005 as the hottest year on record. Overall, the 10 hottest years on record have all occurred in the last 13 years. Extreme weather events – droughts, floods and major typhoons – are becoming more common and destroying farmlands. China’s already stressed water resources are drying out even further. Glaciers, permafrost and sea ice are disappearing, while sea levels are rising and coral reefs dying. The impacts of climate change are already responsible for killing an estimated 315,000 people every year, and damaging ecosystems. Models show that climate change could cause thousands more heat-related deaths per year in many major cities by 2050, independent of population growth. Heat waves can also harm crops, livestock, fish populations and wildlife.

The European heat wave of 2003 killed 14,800 people in France alone and more than 30,000 across the continent. According to the French National Institute of Health, the death rate was 60% higher than normal for that time of year. It was by far the worst heat wave on record.

In a breakthrough paper on climate change impacts, UK scientists concluded with greater than 90% certainty that the probability of a heat wave of that magnitude had doubled because of climate change.

In general, there is likely to be an increase in the risk of drought in the mid-latitudes interiors of continents. The increase in droughts will hurt rich and poor nations alike, but regions that are already experiencing food and water shortages will be the harder hit. A study published by scientists at the National Center for Atmospheric Research in Colorado indicates that the areas of the Earth experiencing ‘very dry’ conditions have more than doubled since the 1970s.

For example, “Africa already has a highly variable and unpredictable climate. Climate change is making that worse. In the Sahel, there has been on average a 25% decrease in annual rainfall over the past 30 years – consistent with climate change models”. Says www.Greenpeace.org

On an other hand: As half of Mexico endures one of the most severe droughts in its history, cloud seeding appears to be a promising way to bring desperately needed rain, although it remains a source of controversy. Cloud seeding involves the spraying of selected clouds with chemicals, usually silver iodide, either from aircraft or from the ground through the use of generators or rockets. This leads to the formation of ice crystals, which grow in size until they reach the necessary weight to fall in the form of rain at lesser altitudes. Silver iodide can cause possible residual injury to humans and mammals with intense or continued but not chronic exposure.

Cloud seeding is practiced along the border between the southern United States and northern Mexico, as well as in Argentina, Chile, Spain and China, the country that uses it most. or his part, Gary Walker of Just Clouds, a company based in the southern U.S. state of Texas dedicated to cloud seeding operations and atmospheric research, told Tierramérica, ‘Properly seeded clouds will make clouds last longer and produce more aerial coverage.’

Cloud seeding is not considered to fall under the category of geoengineering, also known as climate engineering, a concept that refers to any large-scale, human-made effort to manipulate the planet to adapt to climate change.

As a result, it is not subject to the moratorium imposed by the United Nations in 2010 on geoengineering experiments, due to the potential hazard they pose to biodiversity. There are two main areas of geoengineering research: solar radiation management and the removal of carbon dioxide from the atmosphere, to reduce the concentration of this common greenhouse gas.

‘There are at least 25 reasons why geoengineering may be a bad idea,’ according to Alan Robock, a professor of climatology in the Department of Environmental Sciences at Rutgers University in the United States.

These include, for example, ‘disruption of the Asian and African summer monsoons, reducing precipitation to the food supply for billions of people, ozone depletion, reduction of solar power, and rapid global warming,’ he explained to Tierramérica.

Robock fears that ‘the prospect of geoengineering working may reduce the current drive toward reducing greenhouse gas emissions.’ In addition, he said, ‘there are concerns about commercial or military control’ of these technologies.

Mexico, where there are at least nine companies that provide cloud seeding services, particularly in the north of the country, is currently suffering its worst drought in seven decades. Half of the country’s territory is affected by the lack of rain, which is threatening food production and employment in the agriculture sector.

National Geographic says: “A team of British scientists contends that, within 200 years, Earth’s temperatures may become hot enough to kill off half of all existing plant and animal species”.

The researchers from the Universities of York and Leeds in Britain base that dire possibility on a new analysis of the 520-million-year-old fossil record, which links past mass extinctions with cycles of high temperatures. “We could be in the temperature zone in which mass extinctions have occurred by the end of this century, or more likely in the next century,” said Peter Mayhew, the study’s co-author and an ecologist at the University of York. Benton and his colleagues lay out their findings in a paper that appeared in the Proceedings of the Royal Society B.

Measuring in ten-million-year increments, the researchers found a correlation between high temperatures and four of five mass extinctions in Earth’s fossil record.

No other research had examined both the entire globe and the entire fossil record, which begins about 540 million years ago. This analysis makes the strongest case yet for a solid link between temperature and changes in the number of species on Earth.

In Australia, kangaroo populations are likely to be devastated by the increase in average temperature that has been predicted for northern Australia over the next twenty years, researchers said today.

About half the current kangaroo range could disappear as water holes dry up and pasture recedes, a likely consequence of a rise of only two degrees Celsius (3.6 degrees Fahrenheit) in average temperature, they said.

If temperatures rise by an average of six degrees Celsius (11 degrees Fahrenheit), which some climate models predict may happen in Australia by the end of this century, then almost the entire range of kangaroos could be destroyed and at least one species of kangaroo could go extinct. They found that a temperature increase as small as a half-degree Celsius (one degree Fahrenheit) may shrink kangaroos’ geographic ranges. An increase of two degrees may shrink kangaroos’ ranges by 48 percent. A six-degree increase might shrink ranges by 96 percent.

Ritchie says that generally accepted climate models predict temperatures in northern Australia to be between 0.4 and 2 degrees (between 0.7 and 3.6 degrees F) warmer by 2030, and between 2 and 6 degrees (3.6 and 11 degrees F) warmer by 2070.

Finally: WWF, the global conservation organization, warns about the rate of retreat of Himalayan glaciers. The world’s highest glaciers are receding at an average rate of 10 to 15 meters (33 to 49 feet) per year, a rate that is accelerating as global warming increases. Eventually this will mean water shortages for hundreds of millions of people whose water supplies will dry up as the glaciers melt and flow down the rivers to the sea.

Climate change in the already arid African northern sub-region is expected to enhance desertification and bring a gradual decrease in forest cover. In the Sahara and Sahel sub-regions, rainfall is predicted to drop, resulting in soil degradation and an increasing number of dust storms and drought. In northeast Africa, more intense dry periods and shorter wet seasons are expected to affect even huge river systems such as the Blue Nile, leading to serious water shortages and adverse consequences for the agriculture and forestry sectors throughout the region. East and Central Africa will also see its agricultural capacity decline. In West Africa, more frequent and longer dry periods are expected, again threatening crop failures.

“Two things are infinite: the universe and human stupidity; and I’m not sure about the universe.” Albert Einstein

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