Trivia Question: Which trend related to warmer temperatures has predominated? Is the Northern Hemisphere full snow season longer or shorter than it was 40 years ago?

a) Longer
b) Shorter
c) Unchanged

The correct answer is b. Since the early 1970s, the Northern Hemisphere full snow season has been decreasing by 5.5 days per decade. In other words, there are about 19 fewer days of snow cover now than there were 40 years ago. Most of this decline is due to earlier spring melting, with trends in the fall and winter less pronounced. In the United States, sharp declines in the West have been partially offset by an increase in full snow season length in the upper Great Plains.

Seasons: Winter

Source: Choi, G et al. “Changing Northern Hemisphere Snow Season.” Journal of Climate 23 (2010): 5305-5310.

For comparison: The amount of energy it takes to power the global economy is about 474 exajoules, or 830 times the 5.7 x 10¹⁷ joules the bottom 6.5 feet of the atmosphere over land gained between 1973 to 2003. The amount of energy the top 6.5 feet of the oceans have gained over this same period is about 370 exajoules, about the same as annual global energy use, and the top 2,300 meters of the oceans have gained is 4.2 x 10²² joules worth of energy, or about 90 times annual global energy use.

Seasons: Winter, Spring, Summer, Fall

Source: Peterson, TC et al. “Observed changes in surface atmospheric energy over land.” Geophysical Research Letters 38 (2011): L16707.

The mountains in the Pacific Northwest run parallel to the Pacific Ocean and receive abundant wintertime precipitation. Precipitation varies by elevation, with higher elevation areas receiving more snowfall and lower elevation areas getting mostly rainfall during winter. The snowfall at the higher elevations forms snowpack, which creates a natural reservoir that melts gradually during the warm season. This gradual melting provides a steady flow for the region’s streams and rivers; if all of the wintertime precipitation fell as rain instead of snow, the region’s water resources would be much scarcer during the summer and winter flooding would be much more common. Temperatures in the Pacific Northwest have increased by 1.5 degrees Fahrenheit since 1920 and this warming has manifested in a general decline in snowpack and more precipitation falling as rain instead of snow. Compared to 50 years ago, late summer/early fall low flow periods in the region’s rivers are exhibiting average water levels five to nine percent lower and the day of the year with peak flows is coming is an average of 22-27 days earlier in the year. This means that more water is flowing when it is not needed and less is flowing when it is needed the most. This trend is most pronounced in watersheds where at least half of the area is at elevations that have traditionally been high enough for the vast majority of wintertime precipitation to fall as snow instead of rain. Watersheds dominated by transition zones, lower elevation zones where rain/snow mixes are more common and snowpack is small or nonexistent, have not experienced these trends of earlier peak discharge and lower low flows.

Seasons: Summer, Fall

Source: Jefferson, AJ et al. “Seasonal versus transient snow and the elevation dependence of climate sensitivity in maritime mountainous regions.” Geophysical Research Letters 38 (2011): L16402.

Viewer Tip: You can have a “low-impact lawn” by giving these tips at try:

• Tune up. If you use a gas-powered mower or other yard equipment, make sure that equipment is functioning properly and use the correct fuel-oil mixture in two-stroke equipment for maximum efficiency. Check your owner’s manual for details.
• Try a push mower. Gas-powered lawn mowers and other yard equipment produce big emissions that impact our air quality. If you have a small yard, consider using a push mower to eliminate emissions completely!
• Mow at the right time of day.Try to mow during cooler parts of the day – early morning or evening – when ground-level ozone pollution is less likely to form.

(Sources: National Geographic’s Green Guide. “Lawnmower Buying Guide.” http://www.thegreenguide.com/buying-guide/green-energy-efficient-lawnmowers//2; The Clean Air Campaign. “In Your Yard.” www.cleanaircampaign.com; U.S. EPA. “Your Yard and Clean Air.” http://www.epa.gov/otaq/consumer/19-yard.pdf)

Consejos: Es fácil prevenir la contaminación de agua lluvia en su hogar.

• Revise las goteras de su carro y repárelas rápidamente.  Si usted cambia el aceite o anticongelante de su carro, recicle estos materiales en su estación local.  Nunca deseche estos productos afuera ni en el alcantarillado.
• Recoja los desechos de sus mascotas en las aceras y en su patio y deposítelos en un latón de basura.
• Revise el pronóstico local – espere el buen tiempo para usar químicos para el cuidado de su patio como fertilizantes y pesticidas.

(Fuente: U.S. Environmental Protection Agency. “Protecting Water Quality from Urban Runoff.” Disponible en http://cfpub.epa.gov/npdes/stormwatermonth.cfm)

According to the National Weather Service, lightning flashes about 25 million times each year in the United States. Many myths or “urban legends” exist about lightning. Here are a few common myths revealed:

• Myth: Lightning never strikes the same place twice.
  Fact: Lightning does strike the same place more then once – tall, pointy, isolated objects are especially prone to lightning strikes. New York’s Empire State Building is struck almost 100 times per year!
• Myth: A house is 100 percent safe from lightning.
  Fact: A house is a safe place to be during a thunderstorm as long as you avoid things that conduct electricity. This includes corded phones, electrical appliances, wires, TVs, computers, plumbing and metal doors and windows.
• Myth: I should lie flat on the ground if trapped outside when lightning is about to strike.
  Fact: Lying flat on the ground increases the chances of being affected by a ground current.  If you are caught outside, keep moving towards a safe shelter – a building that is fully enclosed with a roof, walls and floor, and has plumbing or wiring – or a fully-enclosed metal-topped vehicle. Always remember “When Thunder Roars, Go Indoors!”

For more lightning myths and facts from the National Weather Service, visit www.lightningsafety.noaa.gov/myths.htm.

Viewer Tip: Get outside and have fun! Many states offer free fishing days during Fishing and Boating Week and June 11 is a fee-free day on National Forest lands.  Remember these simple tips to stay safe and healthy while fishing or boating.

• Be prepared for all kinds of weather. Check your local forecast and bring a jacket or sweater for cool mornings and evenings.  Bring rain gear along, too.
• Listen carefully. If you are outside and hear thunder, immediately get out of and away from ponds, lakes and other water bodies. Head for a substantial building or an enclosed, metal-topped vehicle.
• Protect your skin. Water reflects sunlight, which can increase the amount of UV reaching your skin. Wear sunscreen and lightweight, light-colored clothing.
• Cover your head and your toes. Wear a hat and sunglasses to protect your eyes from glare, and sturdy shoes to protect your feet from sharp rocks.  If you are in a boat, wear shoes that will prevent slipping.

Visit www.takemefishing.org for information about getting a fishing license and finding family-friendly fishing spots.

(Sources: C. Charles, R. Louv, L. Bodner, and B. Guns.  January 2008. “Children and Nature 2008: A Report on the Movement to Reconnect Children to the Natural World.” The Children and Nature Network, http://www.cnaturenet.org/uploads/CNMovement.pdf; Wells, N. and Lekies, K. “Nature and the Life Course: Pathways from Childhood to Adult Environmentalism. Children, Youth and Environments 16(1), 2006.” http://www.colorado.edu/journals/cye/16_1/16_1_01_NatureAndLifeCourse.pdf; National Environmental Education Foundation, Health and Environment Program. “Fact Sheet: Children’s Health and Nature.” http://www.neefusa.org/assets/files/NIFactSheet.pdf; Recreational Boating and Fishing Foundation, Take Me Fishing – Fishing in Warm Weather. http://www.takemefishing.org/assets/downloads/fishing_in_warm_weather.pdf; National Weather Service, www.lightningsafety.noaa.gov)

Photo: National Parks Service

Aunque la Tierra ha experimentado calentamiento durante el último siglo, no todos los lugares se han calentado de manera tan intensa, y algunas zonas han visto enfriamiento.  La costa peruana, una de las zonas más ricas para la pesca, es una de las regiones que ha visto un enfriamiento.  Las especies que habitan las aguas peruanas se nutren del afloramiento, lo cual es el movimiento de aguas frías y ricas en nutrientes desde el fondo del mar hacia la superficie.  El afloramiento se ha intensificado desde los años 1950, ya que la temperatura de la superficie del mar ha enfriado 0,05 grados Fahrenheit por año durante este período.  Este fortalecimiento está vinculado a la intensificación de vientos costeros que halan agua desde las profundidades hacia la superficie.  Las causas de esta intensificación de los vientos no es bien conocida, pero la diferencia en temperatura entre el mar y la tierra ha aumentado, y esto podría ser una razón.  Los fuertes vientos y el afloramiento han beneficiado las especies marinas de la región debido a la abundancia de nutrientes.  Sin embargo, la fuerza del viento puede llegar a un punto en el cual es tan fuerte que provocan una turbulencia que impide el desarrollo de fitoplancton, lo cual es un elemento esencial de este ecosistema

(Fuente: Gutiérrez, D et al. “Coastal cooling and increased productivity in the main upwelling zone off Peru since the mid-twentieth century.” Geophysical Research Letters 38 (2011): L07603.)

Consejos: Algunas plantas encorvan sus hojas durante el día para mantener su superficie fuera de los rayos del sol.  Esto es normal si las hojas regresan a su postura natural al anochecer.  Debe preocuparse si las hojas no regresan a su postura normal o se tornan amarillas.  Para evitar estos problemas, siembre plantas nativas o adaptadas al clima local.  Ponga sus plantas sensibles al sol bajo techo o en la sombra.  El mantillo (o “mulch”) también puede insular las raíces de las plantas en caso de temperaturas extremas.

Esta información fue provista por el Centro Flor Silvestre Lady Bird.  Para más información visite www.wildflower.org.

Viewer Tip: An easy way to find products with safer surfactants is to look for the U.S. Environmental Protection Agency’s Design for the Environment logo on the label of soaps, detergents and household cleaners.  Products with the Design for the Environment label do not contain harmful surfactants or other problematic chemicals.

This information is provided by the U.S. EPA. You can find a list of household cleaning products that have the Design for the Environment logo at www.epa.gov/dfe.

Viewer Tip: Plant leaves may droop mid-day, which keeps more of their surface out of direct sunlight and helps keep them cool. This is okay if the leaves perk up once the sun goes down. The same is true when wilting occurs early spring when plants carry a lot of tender new growth. Be concerned when a plant doesn’t perk up in the evenings during hot weather or when you see leaf scorching – sun-exposed leaves turning yellow. To avoid weather woes, stick with plants that are native or adapted to your region. Create an open-sided tent over any heat-sensitive plants using a frame and shade material if needed. Mulch also helps insulate a plant’s roots from weather extremes.

This information is provided by the Lady Bird Johnson Wildflower Center. Learn more at www.wildflower.org.

Viewer Tip: Native plants need very little fertilizing – if any at all. The type of container you use will determine how often plants need water, with clay and other porous materials drying out faster. Good drainage is important so plants don’t rot.  And remember that roots need adequate space in a pot to grow.

This information is provided by the Lady Bird Johnson Wildflower Center. Learn more at www.wildflower.org.

Viewer Tip: Installing a rain barrel can help you save money and help the Anacostia River. Now that makes dollars and sense! Learn more at www.anacostia.net.

This information is provided by the U.S. Environmental Protection Agency.

Photos for use on-air and online:

Rain barrel in Montgomery County
Click to download full size image.

Rain barrel in Rockville, MD.
Click to download full size image.

Viewer Tip: Protect your home from wildfire! Thirty feet around your house should be a “lean, green and clean” defensible space:

• Lean: Prune trees and shrubs, and make sure that overhanging tree branches are no less than 15 feet from any structure. The lowest branches on trees should be six- to ten-feet from the ground.
• Green: Plant healthy, fire-resistant plants. Your local garden center or County Extension Office can help you find plants that are right for your property and climate.
• Clean: Remove easily flammable vegetation, including leaves, dead wood and firewood, and dry grass.

Find additional tips to protect your home from wildfire at www.firewise.org.

Seasons: Spring, Summer, Fall, Winter

(Sources: FireWise. “Home Safety: Keeping Landscapes Lean, Green, Clean – and Firewise.” http://www.firewise.org/newsroom/files/comm_guide/Comm_Guide_3_Materials/NAPS_LEAN_%20CLEAN_GREEN.pdf)

For Comparison: A clock radio uses about four watts of power. Earth’s surface is about 508,900,000,000,000 square meters.

Seasons: Winter, Spring, Summer, Fall

(Sources: Wang, K and Liang, S. “Global atmospheric downward longwave radiation over land surface under all-sky conditions from 1973 to 2008.” Journal of Geophysical Research: Atmospheres 114 (2009): D19101 and Stephens, GL. “The role of downward long-wave radiation in water vapor feedback and climate change.” The 13th Conference on Cloud Physics/13th Conference on Atmospheric Radiation. Portland, Oregon. 28 June 2010. Accessed Online 6 February 2011 <http://ams.confex.com/ams/13CldPhy13AtRad/techprogram/paper_171462.htm>.)

Viewer Tip: Many commuters drive alone. Give these tips a try to slash time spent on the road and reduce air pollution:

• Telecommute. If you are able to work from home, give it a try! Telecommuting one day per week for a year can save the typical commuter 1200 miles on his or her vehicle and 58 gallons of gas.
• Carpool. A vehicle with four passengers achieving 15 miles per gallon is 2.4 times more efficient than four small sedans with one passenger, each getting 25 miles per gallon.
• Walk or bike. Leave the car at home for short trips to save gas and money.

Seasons: Spring, Summer, Fall, Winter

(Source: Texas Transportation Institute. Urban Mobility Report 2010. Released in December 2010. Available from: http://tti.tamu.edu/documents/mobility_report_2010.pdf; Federal Highway Administration. “It All Adds Up to Cleaner Air.” www.italladdsup.gov)

Viewer Tip: Many commuters drive alone. Give these tips a try to slash time spent on the road and reduce air pollution:

• Telecommute. If you are able to work from home, give it a try! Telecommuting one day per week for a year can save the typical commuter 1200 miles on his or her vehicle and 58 gallons of gas.
• Carpool. A vehicle with four passengers achieving 15 miles per gallon is 2.4 times more efficient than four small sedans with one passenger, each getting 25 miles per gallon.
• Walk or bike. Leave the car at home for short trips to save gas and money.

Seasons: Spring, Summer, Fall, Winter

(Source: Texas Transportation Institute. Urban Mobility Report 2010. Released in December 2010. Available from: http://tti.tamu.edu/documents/mobility_report_2010.pdf; Federal Highway Administration. “It All Adds Up to Cleaner Air.” www.italladdsup.gov)

Viewer Tip: Many commuters drive alone. Give these tips a try to slash time spent on the road and reduce air pollution:

• Telecommute. If you are able to work from home, give it a try! Telecommuting one day per week for a year can save the typical commuter 1200 miles on his or her vehicle and 58 gallons of gas.
• Carpool. A vehicle with four passengers achieving 15 miles per gallon is 2.4 times more efficient than four small sedans with one passenger, each getting 25 miles per gallon.
• Walk or bike. Leave the car at home for short trips to save gas and money.

Seasons: Spring, Summer, Fall, Winter

(Source: Texas Transportation Institute. Urban Mobility Report 2010. Released in December 2010. Available from: http://tti.tamu.edu/documents/mobility_report_2010.pdf; Federal Highway Administration. “It All Adds Up to Cleaner Air.” www.italladdsup.gov)

Viewer Tip: Many commuters drive alone. Give these tips a try to slash time spent on the road and reduce air pollution:

• Telecommute. If you are able to work from home, give it a try! Telecommuting one day per week for a year can save the typical commuter 1200 miles on his or her vehicle and 58 gallons of gas.
• Carpool. A vehicle with four passengers achieving 15 miles per gallon is 2.4 times more efficient than four small sedans with one passenger, each getting 25 miles per gallon.
• Walk or bike. Leave the car at home for short trips to save gas and money.

Seasons: Spring, Summer, Fall, Winter

(Source: Texas Transportation Institute. Urban Mobility Report 2010. Released in December 2010. Available from: http://tti.tamu.edu/documents/mobility_report_2010.pdf; Federal Highway Administration. “It All Adds Up to Cleaner Air.” www.italladdsup.gov)