background preloader


Facebook Twitter

Stanford scientists explain the state of California's drought. Climate change has contributed to droughts since 1900, and is likely to get worse, says tree-ring study. Using studies of tree rings going back centuries, scientists have unearthed clear evidence that the rise of human-generated greenhouse gases was having an effect on global drought conditions as early as 1900. A new, first-of-its-kind study by scientists at Columbia University’s Earth Institute, published Wednesday in the journal Nature, largely confirms what climate models have shown.

In the absence of strong historic data on precipitation, those computer models forecast not only future scenarios, but shed light on historical trends. The dovetailing of the tree-ring studies, which correlate to soil moisture, with climate models gives scientists the assurance that the computer models are, in fact, correct, they say. Marvel said that the results, while not unexpected, are nonetheless gratifying. Fingerprinting droughts The tree-ring data analyzed in the study highlight three periods over the past 120 years in which a human fingerprint on drought and moisture is, to varying degrees, evident. What is a Drought? | Live Science. Droughts occur in nearly all types of climate. Of all the weather-related phenomena that can cause severe economic impacts in the United States, droughts come in second only to hurricanes, according to the National Climatic Data Center. But unlike hurricanes, which are easily identified and straightforward to classify in terms of wind speeds, droughts are much tougher to define.

Definition of drought Most people think of a drought as a period of unusually dry weather that persists long enough to cause problems such as crop damage and water supply shortages. But because dry conditions develop for different reasons, there is more than one definition of drought. "Drought is caused by not only lack of precipitation and high temperatures but by overuse and overpopulation," said David Miskus, a drought expert and meteorologist at the National Oceanic and Atmospheric Administration's (NOAA) Climate Prediction Center. Here are descriptions of the four main categories of drought: Tracking drought.

Causes of Drought: What's the Climate Connection? Drought ranks second in terms of national weather-related economic impacts, with annual losses nearing $9 billion per year in the U.S. [1] Beyond direct economic impacts, drought can threaten drinking water supplies and ecosystems, and can even contribute to increased food prices. Within the last decade, drought conditions have hit the Southeastern US, the Midwest, and the Western US In 2011, Texas had the driest year since 1895. In 2013, California had the driest year on record. There are different types of drought Drought can call to mind images of dry, cracked earth; low reservoir levels; and barren fields, yet these are actually examples of different types of drought, each of which is measured differently. We most often think about drought in relation to precipitation, assessing the degree of dryness (in comparison to a local or regional average) and the duration of the dry period.

Climate change affects a variety of factors associated with drought We should: References. Drought. A drought is a period of time when an area or region experiences below-normal precipitation. The lack of adequate precipitation, either rain or snow, can cause reduced soil moisture or groundwater, diminished stream flow, crop damage, and a general water shortage. Droughts are the second-most costly weather events after hurricanes. Unlike with sudden weather events such as hurricanes, tornadoes, and thunderstorms, it is often difficult to pinpoint when a drought has started or when it has ended. The initial effects of a drought may be difficult to identify right away, so it may take weeks or months to determine that a drought has started.

The end of a drought is hard to identify for the same reason. A drought may last for weeks, months, or even years. Sometimes, drought conditions can exist for a decade or more in a region. Droughts affect people in a several ways. Drought and Climate Change | Center for Climate and Energy Solutions. Climate change increases the odds of worsening drought in many parts of the United States and the world in the decades ahead.

Regions such as the U.S. Southwest will see increased heat, changing rainfall patterns and less snowpack contributing to drought conditions. Even in regions that may not see changes in precipitation, warmer temperatures can increase water demands and evaporation, putting greater stress on water supplies. Recent U.S. droughts have been the most expansive in decades. In 2011, Texas experienced its driest 12 months ever. At the peak of the 2012 drought, an astounding 81 percent of the contiguous United States was under at least abnormally dry conditions. Globally, drought struck several major breadbasket regions simultaneously in 2012, adding to food price instability.

Estimates of future changes in seasonal or annual precipitation in a particular location are less certain than estimates of future warming. Threats Posed by Drought Severe drought can affect: Opinion: What is really scarce in a water drought. Earlier this year, the South African city of Cape Town was told that it would make history by April 16. On that date, dubbed Day Zero, it was expected to become the world’s first major city to run out of water because of an extended drought.

More than 1 million households would face extreme rationing or no water at all as reservoirs went dry. But then something happened. The date was pushed back to June 4. It was not rain that helped delay the threatened cutoff. The city still has far to go to adjust its supply and demand of water. In California, for example, the state’s Water Resources Control Board plans to permanently reinstate some watering bans and conservation programs as a result of a new drought.

Worldwide, the availability of water is in decline as populations rise and people move to cities. This point was made in a 2016 book, “Water is for Fighting Over and Other Myths about Water in the West,” by John Fleck of the University of New Mexico. Sign In. Sign In. Opinion: What is really scarce in a water drought. What is a drought? A drought is a period of time with little or no rain or snow. A short-term drought may last for weeks or months, while a long-term drought may last for years. Droughts can be bad for the environment and food production. Responding to the effects of drought is important to sustainability. Human activity can increase a drought's severity through poor water use and agricultural practices. Climate scientists agree that human activity influences weather patterns that cause drought. How Droughts Happen Atmospheric conditions are the main cause of droughts and the first of a chain of factors. Clouds contribute to the uneven heating of the Earth's surface, which is the source of wind.

How Humans Make Droughts Worse Droughts occur naturally, but humans can make them more devastating. The National Aeronautics and Space Administration (NASA) conducted a study in 2015. California's Drought Drought in California has wide-reaching effects. California suffered a long-term drought from 2011 to 2017.