Global warming: USGS study shows 20 percent decline in Rocky Mountain snow cover since 1980

Posted on May 23, 2013 by Bob Berwyn

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Sparse January snow across the Colorado Plateau in January 2013. Bob Berwyn photo.

Drop linked primarily with warmer spring temperatures

By Summit Voice

SUMMIT COUNTY — Long-time skiers often say that skiing was better in the good old days, and new research from the U.S. Geological Survey suggests that those claims are based on more than nostalgia — notwithstanding the occasional bumper crop of powder like in 2010-2011.

After taking an in-depth look at snowfall and temperature records, federal scientists said warmer spring temperatures since the 1980s have caused an estimated 20 percent loss of snow cover across the Rocky Mountains of western North America — especially at lower elevations where temperatures have the greatest effect. (more…)

Filed under: climate and weather, Colorado, El Niño, Environment, global warming, La Niña, seasons, Snow and weather, water | Tagged: , | Leave a Comment »

Climate: Does El Niño drive West Antarctic warming?

Posted on April 17, 2013 by Bob Berwyn

Ice cores suggest current climate is in the natural range of variability

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Climate scientists track Antarctic changes, Bob Berwyn photo.

By Summit Voice

FRISCO — Ice cores from West Antarctica spanning the last 2,000 years suggest that recent warming and glacier loss in the region is comparable to other warm periods during that span.

Most of the recent warming may be related to powerful El Niño phases in the tropical Pacific in the 1990s, said University of Washington researcher Eric Steig. The ice core record shows similar temperature spikes in the 1830s and 1940s, he said, adding that the recent warming  cannot be attributed with confidence to human-caused global warming.

Steig built on previous research showing that rapid thinning of Antarctic glaciers was accompanied by rapid warming and changes in atmospheric circulation near the coast. The new study suggests that the 1990s were not all that different from some of those earlier warm spells. (more…)

Filed under: Antarctica, climate and weather, El Niño, Environment, global warming | Tagged: , , , | Leave a Comment »

Report: Global warming not a big factor in 2012 drought

Posted on April 12, 2013 by Bob Berwyn

Natural climate variability the biggest player, scientists say

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Drought conditions persist across the central part of the country.

By Bob Berwyn

SUMMIT COUNTY — Last summer’s crippling Great Plains drought can’t definitively be linked with global warming, according to a team of federal scientists from various agencies. In a new report issued this week, the researchers said the drought was probably caused by a confluence of natural climate variations that might only come together in a similar constellation once a century.

Cyclical variations in ocean temperatures — especially the combination of a cooler-than-average Pacific Ocean and a warm phase of the North Atlantic Multidecadal Oscillation may have nudged the region toward drought conditions, but those factors tend to be more of a factor in suppressing winter precipitation. (more…)

Filed under: climate and weather, Drought, El Niño, global warming, La Niña, Uncategorized | Tagged: , , , , , , | 2 Comments »

Climate: Study looks at changing monsoon patterns

Posted on March 22, 2013 by Bob Berwyn

Natural climate variables so far outweigh global warming impacts

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The North American monsoon is an important climate factor in the Rocky Mountains.

By Summit Voice

SUMMIT COUNTY — The timing and amount of monsoon rains in the northern hemisphere have important economic and environmental ramifications, for example for farmers in Asia and the wildfire season in the southwestern U.S.

As a result, climate researchers have been trying to determine how the Earth’s steady warming will affect those seasonal rainfall patterns, and so far, the jury is still out. Some recent research has suggested that the timing of the North American monsoon might be delayed, while other studies have indicated that there could be an overall increase in monsoon precipitation.

In one of the latest studies, scientists with the International Pacific Research Center, University of Hawaii at Manoa, say that monsoon rainfall patterns appear to more influenced by natural long-term swings in ocean surface temperatures. The Interdecadal Pacific Oscillation or mega-El Niño-Southern Oscillation, which has lately been in a mega-La Niña or cool phase is one key factor, and shifts in the Atlantic Multidecadal Oscillation, also contributes to the intensification of monsoon rainfall. (more…)

Filed under: climate and weather, El Niño, global warming, La Niña | Tagged: , , , , , | 2 Comments »

Colorado: No El Niño, no La Niña – what’s driving the weather?

Posted on March 18, 2013 by Bob Berwyn

Spring outlook trends toward warm and dry conditions

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The Madden-Julian Oscillation has played a role in Colorado weather this winter.

By Summit Voice

FRISCO — With neither El Niño or a La Niña conditions in the Pacific Ocean, long-range weather forecasters have been struggling to develop confidence in their outlook for the coming spring season — a critical time for much of the West in terms of getting some relief from drought conditions.

A wet and cool spring could at least take the edge off the drought in some areas, helping to maintain stream flows and reduce the potential for massive and dangerous wildfires. Conversely, a return to last year’s very dry and warm spring pattern would spell trouble for places like Colorado.

So if the El Niño-La Niña cycle isn’t driving the weather, what is? What we do know is that conditions over the Pacific Ocean are the key to understanding exactly what path storms will take across the western United States, and that conditions in the North Atlantic can also be a factor. (more…)

Filed under: climate and weather, Colorado, Drought, El Niño, La Niña, Summit County Colorado, Weatherblog | Tagged: , , , , , | 1 Comment »

Global warming: Hottest summer ever Down Under

Posted on March 2, 2013 by Bob Berwyn

Australia, parts of Africa and South America report record-high readings

Six of the hottest ten summers on record have occurred this century, and only two occurred before 1990.

Six of the hottest ten summers on record have occurred this century, and only two occurred before 1990.

By Summit Voice

FRISCO — At the start of meteorological autumn for the southern hemisphere, The Australian Bureau of Meteorology reports that the country recorded its hottest-ever summer season, breaking the 1997-1998 mark by 0.1 degrees Celsius.

The most extreme heat was in the beginning of January, when a heat wave settled across much of Australia, including Tasmania, leading to wildfires and record-high readings in parts of the country, with temperatures soaring as high as 49.6 degrees Celsius (121 degrees fahrenheit). (more…)

Filed under: climate and weather, El Niño, Environment, global warming, seasons | Tagged: , , , | 3 Comments »

New study helps pinpoint El Niño impacts

Posted on February 9, 2013 by Bob Berwyn

Findings could help improve long-range winter forecasts

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Shifting cycles of warmer and cooler water in the central Pacific influence weather patterns around the world.

By Summit Voice

FRISCO — A new study that sorts El Niño events into two categories could help forecasters develop better long-range forecasts to predict how the periodic warming of equatorial East Pacific waters may affect winter weather.

Part of the data for the research came from an array of buoys across the Pacific called the TAO-Triton array. The buoys observes conditions in the upper ocean to forecast El Niño months in advance, and for monitoring it as it grows and decays.

After analyzing all El Niño events since 1979, the NOAA and University of Washington scientists said the El Niños that show a drop in outgoing long-wave radiation from the tops of deep convective clouds are the ones that tend to play havoc with winter weathers. (more…)

Filed under: climate and weather, Drought, El Niño, seasons | Tagged: , , , , | 5 Comments »

Climate: Indian Ocean temps drive East African droughts

Posted on January 19, 2013 by Bob Berwyn

Study may unlocks new climate clues

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Wet conditions in coastal East Africa are associated with cool sea surface temperatures in the eastern Indian Ocean and warm sea surface temperatures in the western Indian Ocean, which cause ascending atmospheric circulation over East Africa and enhanced rainfall. (Courtesy Jessica Tierney, et al, 2013)

By Summit Voice

FRISCO — A new study may help forecast drought conditions in the oft famine-stricken and geopolitically crucial Horn of Africa. More than 40 million people in the region often live in exceptional drought conditions, most recently in 2010-2011, when the worst drought in decades triggered a humanitarian crisis.

It’s long been clear that El Niño can affect precipitation in the region, very little is known about the drivers of long-term shifts in rainfall. But the study suggests that temperatures in the Indian Ocean may be the key to understanding precipitation patterns in East Africa.

“The problem is, instrumental records of temperature and rainfall, especially in East Africa, don’t go far enough in time to study climate variability over decades or more, since they are generally limited to the 20th century,” said Woods Hole Oceanographic Institution geologist Jessica Tierney, lead author of the paper published in the journal Nature. (more…)

Filed under: climate and weather, Drought, El Niño, global warming, La Niña | Tagged: , , , | 1 Comment »

New coral data traces 7,000 years of El Niño history

Posted on January 4, 2013 by Bob Berwyn

20th century oscillations show intensification that may be linked with global warming

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A NOAA graphic showing early January 2012 ocean surface temperature anomalies.

By Summit Voice

SUMMIT COUNTY — Atmospheric scientists say they’ve used coral records to trace the history of El Niño cycles going back about 7.000 years, showing that 20th century oscillations  are much stronger than those captured in the fossil record.

But the study also showed large natural variations in past ENSO strength, making it difficult to attribute the 20th century intensification of ENSO to rising carbon dioxide levels. Such large natural fluctuations in ENSO activity are also apparent in multi-century climate model simulations, but the 20th century intensification stands out as statistically significant and could be linked with global warming.

The new information will help assess the accuracy of climate model projections for 21st century climate change in the tropical Pacific. (more…)

Filed under: climate and weather, El Niño, Environment | Tagged: , , , , , , , | Leave a Comment »

Climate: October 2012 ties for the 5th-warmest on record

Posted on November 15, 2012 by Bob Berwyn

Year-to-date the 8th-warmest for Planet Earth

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By Summit Voice

FRISCO — Much of Europe, North Africa and South America reported warmer than average temperatures in October, while parts of North America and central Asia were cooler than average.

Taken all together, the average global October temperature was tied with 2008 as the fifth-warmest on record, 1.13 degrees above average, based on data going back to 1880, according to the latest monthly update released this week by the National Climatic Data Center.

Land surface temperatures were the eighth-warmest on record, while sea surface temps tied with 2004 as the fourth-warmest. For the year to-date, 2012 is the eighth-warmest on record, at 1.04 degrees above the 20th century average, and marks 332 months in a row with temps above the historical average. (more…)

Filed under: climate and weather, El Niño, global warming, La Niña | Tagged: , , , , | Leave a Comment »

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