Crazy Weather & Global Warming

In the first 6 weeks of 2014, the world spawned some of the most severe weather in hundreds of years, including record snowfall in the Midwest and Great Lakes, record cold in the US northeast, ice storms in the southeast, record drought in the southwest, record flooding and windstorms in the UK, unseasonal warming in Scandinavia and Russia, record snowfall in the southern Alps, record flooding in Italy, and record heatwaves and wildfires in Australia, Argentina, and Brazil.

Despite the record snow, ice, and freezing temperatures in some areas, the world continued its long term upward warming trend. NOAA reported that 2013 was tied with 2003 as the warmest year on record. What’s going on?

According to a paper presented this month at a meeting of the American Assn. for the Advancement of Science in Chicago, a weakening jet stream caused by Arctic warming is a possible cause. The polar jet stream is a high-altitude air current with wind speeds of 100 to 120 mph (160 to 200kph) that acts as a weather conveyor belt. When Arctic temperatures stay cold, the jet stream blows stronger and tends to stay in place, bringing normal winter weather to North America, Europe, and Asia.

In January, 2014, the air temperature over the Arctic Ocean was 2 to 4˚C (4 to 7˚ F) higher than average, and 7 to 8˚C (13 to 14˚ F) higher than average over Greenland and Alaska. As the Arctic warms, the jet stream weakens and begins sinking south of its polar route. At the same time, Arctic sea ice is melting at a record rate, exposing more ocean to the rays of the sun. The warmer ocean water in turn accelerates Arctic warming. More rapid evaporation pumps extra moisture into the atmosphere.

A sinking jet stream carries the moisture-laden high-altitude cold Arctic air south into the Midwest and southeast, and across the Atlantic to Europe. While southern Europe is experiencing record rains and snowfall, northern Europe, normally very cold in January and February, is basking in abnormally warm temperatures. With the glaciers and polar ice caps melting at a record rate, sea ice contracting, and oceans warming, it seems obvious that global warming is here, and to some extent driving the world’s current radical weather patterns. The weather will become more radical and storms more intense as the earth gets warmer.

But what is driving global warming? The UN’s International Panel for Climate Change (IPCC) has concluded from all available scientific evidence that it is 95% likely that most of the rise in global temperature since the middle of the 20th Century is due to emissions of greenhouse gases, deforestation, and other human activities.

If greenhouse emissions continue at their present rate the IPCC computer models predict our planet will warm 5˚C (9˚ F) by 2100, and by 10˚C (18˚F) during the following century. The earth is now warmer than it has been since the end of the last ice age 11,300 years ago. If we don’t drastically reduce our carbon-based emissions and start relying more on alternative fuels, are we headed for another ice age? Or another age hot enough for dinosaurs?

 

 

 

 

 

 

A Water-Scarce Future?

The UN’s Intergovernmental Panel on Climate Change forecasts that by 2030 global water requirements may outstrip sustainable water use by 40%. In other words, we’ll be using 40% more water than is being replaced by rain and snowmelt. Global warming, rapid population growth, and more wealth in emerging economies are coming together in a perfect storm of increasing demand and falling supply. Without the intervention of some kind of water conservation and management plan, the world’s water tap could one day go dry.

Although 75% of the earth’s surface is covered by water, almost all of that is ocean saltwater. Only 2.5% of earth’s water is fresh water, and 2/3 of that is locked away in glaciers and icecaps. Of the stock of fresh water available, 99% is stored in underground aquifers. Maintaining underground water levels is a balancing act. No more water should be withdrawn than the amount replaced by rain and snowmelt. But with a changing climate that brings less rain and snow, and a growing population that needs more food and more water to grow the food, it is becoming increasingly difficult to maintain that balance.

A team of scientists using data from NASA’s twin Gravity Recovery and Climate Experiment (GRACE) satellites, found that the Tigris & Euphrates basin that includes parts of Turkey, Syria, Iran, and Iraq, lost 117 million acre feet (144 cubic kilometers) of stored fresh water between 2003 and 2010. That’s equivalent to the amount of water in the Dead Sea, and nearly as much as in Lake Tahoe. 40% of the loss was attributed to evaporation of surface water in reservoirs, lakes, and rivers, and 60% to over-pumping of groundwater from the areas’ aquifers. Matt Rodell of Goddard Space Flight Center, co-author of the NASA study, said, “Groundwater is like your savings account. It’s okay to draw it down when you need it, but if it’s not replenished, eventually it will be gone.”

The same problem confronts water users in other arid and semi-arid parts of the world, including Australia, southern Africa, northern Brazil, the Mediterranean basin, and the U.S. southwest. Persistent drought in these areas is causing farmers and other water users to withdraw ground water faster than nature replaces it. According to UN figures, ground-water extraction globally has tripled in the past 50 years. Ground-water withdrawals in India and China have risen tenfold during that period. Aquifer levels in India are sinking 4 meters (13 ft) a year. Half the global population lives in countries where water tables are falling rapidly.

Some scientists believe this negative trend can be slowed or reversed by application of a few simple remedies. Perhaps the most important is improving the efficiency of agricultural irrigation.  If crop flooding, which is still used in many parts of the world, can be replaced with drip irrigation and use of soil moisture sensors, millions of acre feet of water could be saved every year. Recycling wastewater, repairing leakage in water-delivery pipes, and regional water-sharing arrangements are also reliable ways to save water. Individuals can save water by using washing machines and dishwashers only for full loads, by not overwatering lawns and plants, and by sweeping instead of washing down outdoor areas.

Whether conservation measures alone will be enough to keep the taps open remains to be seen.

 

 

 

 

 

Groundwater Sinking to Crisis Levels

Will the world be facing a severe food shortage within the next few decades? According to a number of scientific studies, the answer is quite likely yes, unless conservation measures can be taken to reverse the over-pumping of groundwater. Much of the world food supply is grown by using groundwater for irrigation. Worldwide, aquifer levels are dropping rapidly because far more water is being withdrawn from them than rain and snow can replace. The highest rates of groundwater loss occur in China, India, California’s Central Valley, and the southern high plains areas of Western Kansas and the Texas Panhandle.

A University of Texas study published in May, 2012, indicates that groundwater depletion in the high plains and in California’s Central Valley threaten to cripple agricultural production in two of America’s most important food producing regions. Between 2006 and 2009, farmers in the Central Valley pumped out enough groundwater to fill Lake Mead, or approximately 8 trillion gallons (approximately 25 billion cubic meters). This rate of withdrawal far exceeds nature’s recharge rate. As a consequence, the water level in the underlying Central Valley Aquifer System has dropped 400 feet (120 meters) since the first half of the 20th Century.

The high plains states of South Dakota, Colorado, Wyoming, Nebraska, Kansas, and Texas draw water from the huge Ogallala Aquifer. However, crop irrigation in the Texas Panhandle and Western Kansas, only 4% of the total high plains land area, accounts for one third of the aquifers water depletion. Since 1950, the level of the Ogallala has dropped 300 feet (90 meters). At the present rate of withdrawal, and with a low rate of replenishment due to local dry conditions, the southern high plains will not have enough water to support agriculture within 30 years.

The high plains and the Central Valley account for the much of the nation’s food supply, producing fruits, vegetables, and grains worth $57 billion annually.

Worldwide groundwater depletion rose 230% from 33 trillion gallons (126 billion cubic meters) a year In 1960, to 75 trillion gallons (283 billion cubic meters) a year in 2000. With global warming bringing longer and hotter drought periods, the natural recharge rate is expected to keep dropping, along with the water levels in the underground aquifers. 70% of groundwater withdrawal is used to irrigate crops. One simple way to conserve water is the use of drip irrigation instead of the flooding method presently used by many farmers. Unless such strict groundwater conservation methods are strictly adhered to by farmers everywhere, world food supply will decline while world population continues to expand, creating an inevitable food shortage crisis.

Floods, Fires, & La Niña

During the spring and early summer of 2011, the U.S. Northern Plains states of Montana, North Dakota, South Dakota, Iowa, Nebraska, and Missouri endured torrential rains, heavy snowmelt, swollen rivers, and near-record floods. During this same period, the south central and southwestern states were locked down in a 10-month-long drought, with record heat and massive wildfires. This split personality in the weather is largely attributable to La Niña, a climatic phase in which the equatorial Pacific Ocean turns cooler than normal, creating a weather pattern that sends heavy rain to the northern states and dry conditions to the U.S. southern tier.

Arizona and New Mexico wildfires. The Wallow fire in Arizona’s White Mountains burned for more than a month, blackening 866 square miles (2,240 square kilometers) (553,000 acres) (224,000 hectares) of national forest land before containment. High heat, strong winds, rugged terrain, and lack of rain made the blaze especially difficult to contain for the 1,300 firefighters on the line.

In neighboring New Mexico, the Las Conchas fire had burned 114,000 acres (46,000 hectares) of Santa Fe National Forest as it approached within 12 miles (20K) of the Los Alamos National Laboratory. More than 1,000 firefighters set up a containment line to keep the flames from reaching the nuclear facility’s waste storage area. A University of New Mexico geologist who studies the history of wildfires, stated that the behavior of southwestern firestorms in the last few decades “is at least as severe and maybe more so than anything we’ve seen since the last ice age.” Los Alamos Fire Chief Donald Tucker said, “We’ve seen fire behavior we’ve never seen down here, and it’s really aggressive.”

Texas drought. Texas has experienced the longest, most persistent drought in the state’s history. The entire state of Texas plus 32 counties in adjoining states were declared a disaster area by the U.S. Dept. of Agriculture. Since August, 2010, the state had been plagued by heat, high winds, and lack of rain. Between November, 2010, and June, 2011, Texas wildfires had burned 3,300,000 acres (1,335,000 hectares). Parched grazing land forced ranchers to thin their herds by prematurely sending cattle to slaughter. Farmers throughout the state suffered extreme crop losses. One farmer said, “It’s so dry, the grass just crackles under my feet.” The June, 2011 high temperature recorded in one Texas city was 117F (47C). All farmers and ranchers in the disaster area are eligible to apply for aid from the U.S. Dept. of Agriculture.

Missouri River flood. As heat and flame seared the southwest, the states in the northern plains fought to keep surging rivers from overflowing their banks. The 2010-2011 snowpack in the Rockies and other western mountain ranges was much heavier than normal, as was the spring runoff. Also, the stormy weather that brought tornadoes to some southern and Midwestern areas brought extremely heavy rain to the northern plains. The rain and runoff filled lakes and reservoirs to overflowing, and released extremely high volumes of water into the Missouri’s tributaries and into the river itself. The USDA estimated that the Missouri overflowed its banks and levees in several key places in Iowa, Nebraska, and Missouri, inundating 550,000 acres of farmland, and submerging a number of rural homes and grain storage and processing facilities.

Souris River flood. The Souris is a Canadian river with its source in Saskatchewan. It runs west to east, dipping south through Minot, North Dakota, then looping back north into Canada to join the Assiniboine River that empties into Lake Winnipeg. The Souris’s volume increases dramatically as it runs south into North Dakota. In this wetter than normal year, the river at maximum flood stage crested 4 ft (1.2m) above a record set 130 years ago. 3,000 homes in Minot were flooded out and 12,000 people evacuated to higher ground.

The role of La Niña. Approximately every 5 years, the ocean water in the tropical Pacific around Australia and Indonesia warms or cools at least 0.5 degrees C (0.9 degrees F). When it turns warmer, the condition is called El Niño. When it cools, it is a La Niña condition. This warming or cooling of the tropical ocean is accompanied by an atmospheric change in the western Pacific called the Southern Oscillation. High pressure sets in during an El Niño, and low pressure during La Niña. The combination of El Niño/La Niña and the Southern Oscillation is referred to as ENSO.

Mainly, El Niño/La Niña conditions impact the weather in countries bordering the Pacific Ocean. During La Niña, South America experiences drought conditions, and Australia and Asia very wet conditions. In the past, La Niñas have lasted 6 to 9 months. In recent years, they have been stronger and lasted longer. The current La Niña that has been the cause of the northern flooding and southern fires and droughts began in May, 2010, and lasted till June, 2011, at which point it began to weaken, but the damage had been done.

Typically, during a La Niña, Western Canada, the Pacific Northwest, Northern California, and the northern Midwestern states have above-average precipitation, while the southwestern and southeastern states have below-average precipitation. This time, the north was excessively wet and cool while the south was excessively dry and hot, indicating that these phases are hitting harder and lasting longer. Some scientists attribute this to global warming, but that is still under study. Also under study are the mechanics of the phenomena. Meteorologists, oceanographers, and other disciplines know what ENSO does, but can’t yet fully explain exactly why it does what it does.

If ENSO behaves as it has in the past, there will be a period of “normal” weather, during which ENSO will not be a factor. That will be followed by an El Niño, when conditions reverse. The northern tier will experience drier than normal conditions, and the southern tier will be wetter than normal.

The 2010-2011 La Niña produced a series of natural disasters while in full sway, including fires, droughts, tornadoes, and floods that killed hundreds and displaced thousands. Most people will be glad to see it go.