Earth Gauge » Plants, Animals and Agriculture

Climate Trivia: Earth’s Green Season

kraus — Mon, 08 Mar 2010 15:01:01 +0000

In the Northern Hemisphere, deciduous trees are beginning to come out of their dormant season and unfurl their leaves. Soon, the greys and browns that characterize America’s broadleaf forests during winter will be replaced the by the greens of spring and summer. Over the last four decades, there has been a global trend in the length of the “green” season, or the period between when leaves emerge in the spring and when they turn color and drop in the fall.

Trivia Question: Since 1970, Earth’s “green” seasons have become…

a) longer
b) shorter

The correct answer is a. Earth’s “green” season – the combined average length of both the Northern and Southern Hemisphere green seasons – is now on average 15 days longer than it was in 1970. This trend has been linked to warmer temperatures, milder winters and higher concentrations atmospheric carbon dioxide.

Seasons: Late Winter, Early Spring

Source: Peñuelas, J et al. “Phenology Feedbacks on Climate Change.” Science 324 (2009): 887-888.

Climate Trivia: El Niño Events and Frost Days – Great Basin

kraus — Mon, 08 Mar 2010 14:54:12 +0000

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, especially plants we grow for food. In the United States over the second half of the 20th century, the average length of the frost free season increased at a rate of two days per decade. How many frost days there are each year is influenced – as is much of our weather – by the El Niño-Southern Oscillation (ENSO), or the periodic warming and cooling of the eastern tropical Pacific. This warming and cooling changes how air in the upper-atmosphere moves, which in turn affects weather across the United States.

Trivia Question: During El Niño years such as this year, when the eastern tropical Pacific is relatively warm, does the Great Basin region have on average…

a. fewer frost days?
b. more frost days?

The correct answer is a. All other things being equal, the Great Basin region experiences fewer frost days during El Niño years compared to La Niña years.

Seasons: Late Winter, Early Spring, Fall

(Sources: Meehl, GA et al. “Current and Future U.S. Weather Extremes and El Niño.” Geophysical Research Letter 34 (2007) L20704 and Easterling, David. “Observed Climate Variability and Change.” NOAA/National Climatic Data Center. Ashville, NC: 31 January 2007 http://www.ametsoc.org/atmospolicy/documents/Easterling-Observed-Change-Jan-07.pdf)

Climate Trivia: El Niño and Frost Events – Pacific Northwest

kraus — Mon, 08 Mar 2010 14:50:05 +0000

Trivia Question: During El Niño years such as this year, when the eastern tropical Pacific is relatively warm, does the Pacific Northwest have on average….

a. fewer frost days?
b. more frost days?

The correct answer is a. All other things being equal, the Pacific Northwest experiences fewer frost days during El Niño years compared to La Niña years.

Seasons: Late Winter, Early Spring, Fall

Sources: Meehl, GA et al. “Current and Future U.S. Weather Extremes and El Niño.” Geophysical Research Letter 34 (2007) L20704 and Easterling, David. “Observed Climate Variability and Change.” NOAA/National Climatic Data Center. Ashville, NC: 31 January 2007 http://www.ametsoc.org/atmospolicy/documents/Easterling-Observed-Change-Jan-07.pdf.

Climate Trivia: El Niño and Frost Events – Eastern U.S.

kraus — Mon, 08 Mar 2010 14:44:28 +0000

Trivia Question: During El Niño years such as this year, when the eastern tropical Pacific is relatively warm, does the eastern U.S. experience on average…

a. fewer frost days?
b. more frost days?

The correct answer is b. All other things being equal, the eastern U.S. experiences more frost days during El Niño years compared to La Niña years.

Seasons: Late Winter, Early Spring, Fall

Climate Trivia: El Niño and Frost Events – Southern U.S.

kraus — Mon, 08 Mar 2010 14:34:45 +0000

Trivia Question: During El Niño years such as this year, when the eastern tropical Pacific is relatively warm, does the southern U.S. have on average…

a. fewer frost days?
b. more frost days?

The correct answer is b. All other things being equal, the southern U.S. experiences more frost days during El Niño years compared to La Niña years.

Seasons: Late Winter, Early Spring, Fall

Climate Number: Two Tons

kraus — Mon, 01 Mar 2010 14:57:07 +0000

Over the past 250 years, the amount of carbon dioxide (CO2) in the atmosphere has risen from 280 parts per million to almost 400. Plants use sunlight to convert this atmospheric carbon into the sugars and starches that make up their tissues. As the amount of carbon in the atmosphere changes, plant growth patterns change as well. Longer growing seasons, the period of the year when freezing temperatures do not restrict growth, as well as warmer temperatures in general, also affect plant growth. All three of these climate trends (more CO2, longer growing seasons and higher temperatures) have been occurring in the forests of America’s Mid-Atlantic region over the past century. During this period, plant growth in these forests accelerated. Each acre accumulates a certain amount of “biomass” each year, which reflects how much carbon these forests take out of the atmosphere and store in their bodies. Each acre of Mid-Atlantic forest is now accumulating about two more tons of biomass each year than they did in 1900.

For Comparison: Two tons is about the same weight as two mature Hereford bulls.

Seasons: Spring, Summer, Fall

Sources: McMahon, SM et al. “Evidence for a recent increase in forest growth.” Proceedings of the National Academy of Sciences 107 (2010): 3611-3615 and “Forests are Growing Faster, Ecologist Discover; Climate Change Appears to be Driving Accelerated Growth.” Science Daily 2 February 2010. Accessed Online 28 February 2010 )

Climate Number: 510 Years

kraus — Mon, 01 Mar 2010 14:49:22 +0000

Better understanding how fluctuations in climate have affected regional wildfire frequency over the past few centuries may help to improve our ability to predict severe wildfire seasons. Some of the West’s older groves have experienced dozens of wildfires over the past few centuries. The trees that survived these fires recorded black scars in their annual tree rings, providing us with the ability to know what year a given area burned. Core samples (profiles of the annual rings taken from a part of the tree trunk) are used to figure out when and where of fires occurred in the past. Enough of these fire scars from a long enough period of time make it possible to investigate the possible links between large scale climate variability and fire in given regions of the West. A recent investigation using core samples from hundreds of trees across the West found that fire years are more common during drought years and the occurrence of drought is controlled by large-scale movements of water in the oceans. Specifically, different phases of the El Nino-Southern Oscillation, the periodic warming and cooling of the eastern tropical Pacific, and the Atlantic Multidecadal Oscillation, the periodic warming and cooling of the North Atlantic, influence the frequency of fire in the West. Fire in all regions of the West is more common when the North Atlantic is warmer. The Pacific Northwest has more fires when the eastern tropical Pacific is warmer and the Southwest has more fires when the eastern tropical Pacific is cooler than average. The oldest trees used in this study had fire records going back to 1400 CE, 510 years ago.

For Comparison: The Mongol Empire was at its peak 510 years ago, with its soldiers sacking cities as far west as Damascus. In Florence, Italy, the Medici family was building the banking empire that would revolutionize western finance.

Seasons: Winter, Spring, Summer

Sources: Kitzberger, T et al. “Contingent Pacific-Atlantic Ocean influence on multicentury wildfire synchrony over western North America.” Proceedings of the National Academy of Sciences 104 (2007): 543-548 and Trouet, V et al. “Fire-climate interactions in the American West since 1400 CE.” Geophysical Research Letters 37 (2010): L04702.

Climate Fact: Prairie Plant Response to CO2 Enrichment

kraus — Mon, 22 Feb 2010 15:17:11 +0000

Changes in the amount of carbon dioxide (CO2) in the air have been shown to affect plant growth rates, the amount and quality of fruit plants produce and how much water a plant releases through evaporation. A study conducted between 1996 and 2001 in the western Great Plains (parts of Colorado and Wyoming) grew several species of native and invasive prairie plants under both elevated and current CO2 concentrations and temperatures. The plants communities grown under elevated CO2 concentrations and temperatures produced about twice as much plant matter as the communities grown under today’s conditions. This growth, however, was accompanied by a decrease in the amount of nutrients the plant matter held. Also, plant species considered to be of poorer quality for livestock became more prevalent under the elevated CO2 and temperature conditions.

Seasons: Winter, Spring, Summer, Fall

Source: Parton, WJ et al. “Projected ecosystem impact of the Prairie Heating and CO2 Enrichment experiment.” New Phytologist 174 (2007): 823-834.

Climate Trivia: Coral Bleaching

espinoza — Mon, 08 Feb 2010 14:04:00 +0000

Some of Earth’s most diverse and colorful ecosystems are shallow-water coral reef ecosystems, which are built on the skeletons of animals called corals. One critical part of these ecosystems, known as zooxanthellae – the single- celled organisms that live in coral skeletons – use their photosynthetic ability to manufacture sugars from the sun, which they give to the corals. This energy, which could be likened to “rent” paid, is necessary to keep the corals alive and the reef ecosystems functioning. Corals need warm waters to survive, which is why they are only found in tropical and subtropical waters. If the water becomes too warm, however, corals “expel” the zooxanthellae and “bleach.” While corals can recover from bleaching events if the exceptionally warm conditions wane, periods of prolonged exposure to these conditions cause the corals to die. When waters in the reefs rise 1.6 degrees Fahrenheit above their long-term monthly averages, they are considered by the National Oceanic and Atmospheric Administration to be in danger of bleaching. El Niño years correspond to elevated sea surface temperatures on a global scale and the El Niño events of 1982-83 and 1997-1998 corresponded to years when coral bleaching was especially widespread.

Trivia Question: During the severe global coral bleaching event of 1998, what percentage of the world’s reef-building corals died?

a. One percent
b. Ten percent
c. 16 percent
d. Less than one percent

The correct answer is c. Sixteen (16) percent of Earth’s corals died during the 1998 bleaching event. Sea surface temperatures in the tropical and sub-tropical Atlantic are the warmest they have been since record keeping began in the 1880’s. The northern hemisphere summer (June, July and August) of 2009 logged the warmest summer global sea-surface temperatures on record.

(Sources: National Oceanic and Atmospheric Administration: NOAA News. “NOAA: Warmest Global Sea Surface Temperatures for August and Summer.” 16 September 2009. Accessed Online 6 February 2010 and Government of Australia: Great Barrier Reef Marine Park Authority. “What is Coral Bleaching?” Accessed Online 6 February 2010 )

Climate Trivia: Ocean vs. Atmosphere Carbon Stocks

espinoza — Mon, 08 Feb 2010 13:56:38 +0000

Carbon is a critical element in the Earth system. Carbon molecules are constantly moving from different states and from reservoir to reservoir. One reservoir is the terrestrial biosphere (the life systems that exist on land), which holds carbon primarily in the form of plant matter and soil. The atmosphere holds carbon in the form of carbon-dioxide gas (CO2) and methane. The oceans also hold carbon, primarily in the form of dissolved CO2 and calcium carbonate. The amount of reactive carbon – carbon in forms that can readily change its chemical state and move from one reservoir to another – in each of these reservoirs is markedly different. The ocean is by far the largest of these three carbon reservoirs.

Trivia Question: The ocean’s carbon reservoir is about how many times the size of the atmosphere’s carbon reservoir?

a. Two times
b. Ten times
c. 25 times
d. More than 60 times

The correct answer is d. The oceans hold more than 60 times the amount of reactive carbon that the atmosphere does.

(Source: Riebesell, U et al. “Sensitivities of marine carbon fluxes to ocean change.” Proceedings of the National Academy of Sciences 49 (2009): 20602-20609)

Climate Trivia: Earth’s Largest Dust Source

espinoza — Mon, 08 Feb 2010 13:50:31 +0000

At any given time, there is about 22 million tons of dust suspended in the atmosphere around us. Dust has important effects on Earth’s climate. It absorbs and scatters incoming radiation, affecting how much sunlight reaches the Earth’s surface and how much is reflected back into space. How much sunlight reaches the Earth’s surface helps drive surface temperatures and rainfall patterns. Dust also serves as a fertilizer – dust from barren regions can travel thousands of miles and fertilize plants that grow in lush regions. The Amazon rainforest is one such lush region that is stimulated by fertilizing dust from afar.

Trivia Question: What region is Earth’s largest single source of atmospheric dust?

a. The Great Basin
b. The Gobi Desert
c. The Sahara Desert
d. The Atacama Desert

The correct answer is c. More dust comes out of Africa’s Sahara Desert than any other region on Earth. The Bodélé Depression in Chad (central Africa) may be Earth’s largest single dust “hot spot.” About half of the dust emitted from the Sahara comes from this 8650 square mile barren lake bed. Each year, about 100 dust plumes rise from the depression. Each plume contains about 700,000 tons of dust.

(Source: Grini, A et al. “Model simulations of dust sources and transport in the global atmosphere: Effects of soil erodibility and wind speed variability.”Journal of Geophysical Research – Atmospheres. 110 (2005): D02205 and Washington, R. et al. “Dust as a tipping element: The Bodélé Depression, Chad.” Proceedings of the National Academy of Sciences 49 (2009): 20564-20571)

Climate Fact: Musk Ox Parasites and Warming

kraus — Mon, 25 Jan 2010 14:31:48 +0000

In the Canadian Arctic, Musk Oxen endure the long winters and short summers that characterize one of Earth’s most extreme environments. The animals have spent millennia adapting to the brutal cold, but now increases in temperature are presenting new problems. A parasitic species of nematode dwells in the musk oxen lungs and too many nematodes can inhibit respiration in the oxen making them more vulnerable to predators. The nematodes have a larval stage in slugs that live on the tundra and require a certain amount of heat to reproduce and move from larvae to adult. Traditionally, the cold has made it difficult for an adult nematode to reproduce each year and instead they would only reproduce once every two years. From the late 1970’s to 1990, temperatures were generally not warm enough to allow the nematodes to reproduce every year. Around the late 1980’s however, a threshold was reached and from 1990 to 2003 the nematodes reproduced most years and their populations expanded both in number and range. A 50 percent decline in the study area’s musk oxen population was observed from 1988 to 1994.

Seasons: Winter, Spring, Summer, Fall

Source: Kutz, SJ et al. “Global warming is changing the dynamics of Arctic host-parasite systems.” Proceedings of the Royal Society B 272 (2005): 2571-2576.

Climate Fact: Lake Warming in California and Nevada

kraus — Mon, 25 Jan 2010 14:29:50 +0000

Air temperatures are fickle – they fluctuate significantly from day to day, from season to season and from year to year. The temperature of a water body fluctuates as well, but is much more constant than the surrounding air temperature. Water has a higher heat capacity than air, which means it takes far more energy to raise the temperature of a given volume of water than a given volume of air. It also means that once warmed, the water must lose lots of energy to fall in temperature. This higher heat capacity causes seasonal changes in water temperature to “lag” behind the ambient air temperature. This phenomenon is easily observable. The air temperature can remain below freezing for weeks before ice cover begins to form on lakes. The higher heat capacity of water means that temperature fluctuations on multi-annual time scales in lake water as a whole are much smoother than temperature fluctuations in the atmosphere, making lakes effective indicators of longer term warming or cooling trends. Records from satellite imaging systems that collect nighttime infrared emissions show that several large lakes in the Sierra Nevada region (Tahoe, Mono, Pyramid, Almanor and Clear Lake) have collectively been warming at a rate of 0.2 degrees Fahrenheit per year since 1992. This trend may have implications for the life in these lakes that has adapted to the traditionally cold high-altitude temperatures.

Seasons: Winter, Spring, Summer and Fall

Source: Schneider, P et al. “Satellite observations indicate rapid warming trend for lakes in California and Nevada.” Geophysical Research Letters 36 (2009): L22402.

Climate Fact: Antarctica’s Subglacial Lakes

kraus — Fri, 15 Jan 2010 16:02:11 +0000

Beneath the Antarctic ice sheet lie some of Earth’s final frontiers – networks of subglacial lakes, many of which have been isolated from the atmosphere for as long as 15 million years. Outlet channels allow these lakes to periodically drain into the ocean, refill and drain again. The largest of these lakes, Lake Vostok, lies about 2.5 miles below the surface of the East Antarctic ice sheet and is about the size of Lake Ontario. Recently, subglacial lakes have attracted the attention and imagination of much of the scientific community for two primary reasons:

• Ice Stream Stability: Ice streams are areas of continental ice sheets where inland ice flows rapidly into the ocean – they can be characterized as “rivers of ice.” Subglacial lakes are an important component of ice stream dynamics. A series of large lakes sit at the onset of the Recovery ice stream, which comprises eight percent of the East Antarctic ice sheet, providing the initial “lubricant” for ice destabilization and movement (which occurs at a rate of about 320 feet per year). The periodic drainage of these lakes can lead to periodic accelerations in ice flow as well. Better understanding the relationship between subglacial lakes and the ice that covers them is crucial to predicting future rates of continental ice loss and sea level rise.

• Unique Ecosystems: Because subglacial lakes have been essentially untouched by sunlight, oxygen and other ecosystems for millions of years, the life that does exist in these lakes is unique and potentially analogous to early life on Earth, particularly life that survived in extensive glacial periods of Earth’s distant past (500-1,000 million years ago). Samples taken from outlet water flowing from a subglacial lake 500 yards below Taylor Glacier in West Antarctica reveal that the microorganisms living there use a series of reactions with sulfate and ferric iron to “breathe” and metabolize the limited organic matter in this virtually oxygen-free environment. Similar reactions have been performed in laboratories, but no where else on Earth have such ecosystems been found. The scouring of the iron rich rocks by the massive ice sheets is thought to be the source of the nutrients that feed this life.

To see depictions of Antarctica’s subglacial lake networks and Lake Vostok, visit http://www.earthgauge.net/climate-facts-image-library#4. These images come from the National Science Foundation and are in the public domain.

Seasons: Winter, Spring, Summer, Fall

Sources: Grom, Jack. “Ancient Ecosystem Discovered Beneath Antarctic Glacier.” ScienceNOW Daily News 16 April 2009. Accessed Online 14 January 2010 and Bell, RE et al. “Large subglacial lakes in East Antarctica at the onset of fast-flowing ice streams.” Nature 445 (2007): 904-907 and Mikucki, JA et al. “A Contemporary Microbially Maintained Subglacial Ferrous ‘Ocean.’” Science 324 (2009): 397-400 and Christner, BC et al. “Limnological conditions in Subglacial Lake Vostok, Antarctica.” Limnology and Oceanography 51 (2006): 2485-2501.

Climate Fact: Nutrition Change and Extreme Weather

espinoza — Mon, 21 Dec 2009 12:31:32 +0000

In Brief: Soybeans may produce more antioxidants during years of extreme temperature and drought.

A study conducted on Maryland soybeans between 1999 and 2002 found that extreme weather events actually increase the antioxidant levels in the soybean crop. 1999 and 2001 growing season temperature and precipitation levels were normal and the crops exhibited normal levels of the antioxidant alpha-tocopherol. Although there were not any abnormalities in the soybean antioxidant levels between 1999 and 2001, it was noted that when the temperature was slightly warmer, antioxidant levels slightly increased. A similar pattern was noted in 2002, when drought and high temperatures dominated Maryland’s weather. During this year, the antioxidant levels in the soybean crops increased by a factor of 3.5.

(Source: United States. USDA. Extreme Weather Boosts Antioxidant Levels in Soybean Seeds. By Rosalie Bliss. Agricultural research service, 17 Dec. 2008. Web. Nov. 2009. )

Climate Number: 4841 Years

kraus — Mon, 30 Nov 2009 16:21:59 +0000

At the ripe-old age of 4,841 years, the Methuselah Tree, a Bristlecone Pine growing in California’s White Mountains, is the planet’s oldest known non-clonal living organism. Bristlecone Pines are found in high elevation locations in the southwestern U.S., where summers are dry and winters are bitterly cold (in the White Mountains they grow between 10,900 and 11,400 feet). Winters here are so cold and long that it takes until mid-June for the average daily temperature to break the 47 degree Fahrenheit mark, a threshold level below which trees are not able to produce wood. An analysis of tree-rings from other Bristlecone Pines growing near Methuselah, as well as two other bristlecone stands several hundred miles away in Mt. Washington and Pearl Peak, Nevada, show that the growth rates of these trees in the second-half of the 20th century was faster than any other time in the last 3,700 years. This is thought to be linked to the nearly two-degree Fahrenheit rise in average daily temperature that has occurred at this location since 1950.

For Comparison: The Methuselah Tree is thought to have germinated in 2832 BCE. This is more than two centuries before the Great Pyramid of Giza was constructed. This is around the time when the first mythical emperors of China lived and when Chinese writing was thought to have originated.

To see a Bristlecone Pine growing in California’s White Mountains, visit: http://www.earthgauge.net/climate-facts-image-library#7. The image comes from the National Oceanic and Atmospheric Administration and is in the public domain.

Seasons: Winter, Spring, Summer, Fall

Source: Salzer, MW et al. “Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes.” PNAS, early addition. Accessed online 26 November 2009

Climate Fact: Cool Crops

espinoza — Fri, 23 Oct 2009 15:08:35 +0000

About 17 percent of America’s total land area is devoted to agriculture and agricultural activities. Half of America’s domestically consumed produce is grown in California, where fruits and nuts are economically important crops. Fruits and nuts require periods each year of cold temperatures (below 45 degrees Fahrenheit) in order to properly develop. Since the 1950’s, the number of cool days has been declining in many parts of California. This decline leads to low yields and a decrease in the quality of these crops. Although the decline in cool days adversely affects fruit and nut crops, in some parts of the State it has aided crops such as oranges and wine grapes.

(Sources: US National Assessment of the Potential Consequences of Climate Variability and Change Sector: Agriculture. US Global Change Research Program. Web. 30 Sept. 2009 and Moser, S, et al. “The Future is Now An Update on Climate Change Science Impacts abd Response Options for California.” California Energy Commision. Web. 30 Sept. 2009 )

Climate Fact: Desert Expansion and Vegetation

kraus — Tue, 29 Sep 2009 18:51:40 +0000

Vegetation “feedbacks,” changes in vegetation as the climate changes, are an important component of Earth’s climate system. At high latitudes, warming tends to allow trees and shrubs to grow faster and expand into previously inhospitable locations. Because trees and shrubs are generally darker than the grasses they overshadow, they absorb more of the sun’s energy and cause the local environment to warm even more – a scenario that illustrates a “positive” vegetative feedback. Positive vegetative feedback was likely an important component of the deglaciations that occurred at the end of past ice ages. Another example of a positive vegetative feedback occurs around Earth’s arid subtropical regions. When subtropical forests dry, trees become scarcer, grass cover expands and forests turn into park-like savannahs. Savannahs absorb about ten percent less solar energy than forests. When less energy is absorbed, there is less convection and less upward motion of air masses. Less upward motion means that there is less moisture convergence at high altitudes and thus less rainfall and more drying, which can lead to the conversion of savannah to desert. Deserts absorb even less energy than savannahs do, further exacerbating this cycle. Attempts to model Earth’s climate without including positive vegetative feedback underestimate the 1950 to 2005 increase in desert cover, which is estimated to be around one million square miles (a ten percent increase over the 55-year period).

Seasons: Winter, Spring, Summer, Fall

Source: Zeng, N and Yoon, J. “Expansion of the world’s deserts due to vegetation-albedo feedback under global warming.” Geophysical Research Letters 36 (2009): L17401.)

Climate Fact: Pacific Brants and Climate Shifts

kraus — Fri, 11 Sep 2009 15:56:03 +0000

The rich waters in Alaska’s Arctic and sub-Arctic estuaries provide the Pacific Brant, a small goose that travels in flocks of as many as 500 birds, with a steady supply of eelgrass (its principle food source) during the summer months. Traditionally (before the late 1970’s), almost 90 percent of the population would spend their summers in Alaska, retreating south to Mexico during the fall and winter months. Since the North Pacific “regime shift” of 1976-1977, a phenomenon that featured noticeable changes in ocean circulation and species distributions/concentrations, the waters in the North Pacific and Bering Sea have been warming. In Alaska, this warming has corresponded to more eelgrass and more favorable conditions for the birds. The regime shift has also corresponded to weakening of the Aleutian Low, the low pressure center that lies near the Aleutian Islands. As the low has weakened, the number of days each autumn when there are favorable tail winds for the migration has decreased. These trends may account for the increase in the number of Pacific Brants spotted in Alaska during the winter. Counts before 1977 would rarely detect more than 3,000 birds. In recent years, the counts have found as many as 40,000 birds.

To view and download a public domain image of a Pacific Brant family, visit the United States Geological; Survey: http://gallery.usgs.gov/photos/09_09_2009_hlc5Fsq11Y_09_09_2009_0.

Seasons: Fall, Winter

Source: U.S Department of Interior, U.S. Geological Survey. “Opting Out of Migration: As Climate Warms, Arctic-Nesting Geese Elect to Winter in Alaska Instead of Mexico.” 9 September 2009. Accessed Online 11 September 2009

Climate Fact: Winter Temperatures and Crop Yields

kraus — Wed, 26 Aug 2009 16:49:50 +0000

Many of America’s most important commercial crops require between 400 and 1800 hours each winter when the temperature is below 45 degrees Fahrenheit. Winter temperatures have been rising steadily across the nation, with the most pronounced trends being witnessed in the upper-Midwest and Northeast. In fact, winter temperatures are rising faster than temperatures in any other season.

To see how winter temperatures are changing in your area, visit http://www.earthgauge.net/climate-facts-image-library#7. This image is featured in the “Global Climate Change Impacts in the United States” report recently published by the U.S. Global Change Research Program. The image is in the public domain.

Season: Winter

Source: Global Climate Change Impacts in the United States, Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson,(eds.). Cambridge University Press, 2009.