Tag Archives: heat

Climate Change in Saguaro National Park

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The saguaro – the classic symbol of the American southwest – is the largest cactus species in the United States and only grows in the Sonoran Desert. Straddling the city of Tucson, AZ, Saguaro National Park protects over 90,000 acres of its namesake cactus. While visiting there recently, I learned how this unique environment is being impacted by climate change.

The Southwest is the hottest and driest part of this country and climate change is making it even more so.  According to the US National Climate Assessment, 2001 through 2010 was the region’s warmest decade on record with temperatures almost 2°F above historic averages. Looking ahead, the report projects continued increases in average annual temperature and a decrease in precipitation, especially in the southernmost part of the region. In a National Park Service (NPS) report on arid lands, the agency says it has already observed a widespread winter and spring warming trend and a lengthening of the frost-free season in the Sonoran Desert.

These warmer conditions are causing a variety of environmental changes in Saguaro National Park. While fewer cacti are dying from severe freeze events, evaporation rates are increasing, making an already parched area even drier. “Arid ecosystems,” the NPS says, “are particularly sensitive to climate change and climate variability because organisms in these regions live near their physiological limits for water and temperature stress.” Even slight changes in the environment can dramatically alter the distribution and abundance of many desert species. On average, the region currently receives less than 12 inches of rain per year.

The phenology, or the timing of natural events, is also being thrown out of sync as the climate changes. The vital rains of the region’s monsoon season traditionally begin in early July, but are projected to arrive later and later in the coming years. This can be a problem for the saguaros, because they have evolved to produce fruit in the beginning of July. While adapted for the dry desert environment, the cacti still depend on adequate rain during the summer growing season for both their own survival and the establishment of seedlings.

Another serious climate change challenge for the Sonoran Desert is the spread of non-native plant species. Buffelgrass, a native of Africa, was introduced to Arizona in the 1940’s for cattle forage. Thriving in the heat, this invasive species is crowding out the native plants (including the cacti), changing the look of the landscape, and increasing the risk of wildfires.

The Sonoran Desert did not evolve with fire as an ecological factor. Lush with vegetation by desert standards, the region usually had large gaps between groups of plants. This helped keep any wildfires small. Now, as the buffelgrass fills in those open spaces, fires can burn hotter and spread much more easily. Adding insult to injury, the buffelgrass grows back after a fire has killed the native plants.

The changing environment is also problematic for the animals that depend on the saguaros for food and shelter. These include a wide array of species, ranging from woodpeckers to coyotes.

Scientists are continuing to monitor and research how additional changes in temperature and precipitation will affect this beautiful and unique place.

Saguaro National Park, Arizona. Photo Credit: The Weather Gamut

Saguaro National Park, Arizona.  Photo Credit: The Weather Gamut

2014: Warmest Year on Record for Planet Earth

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Its official!  2014 was the warmest year ever recorded on planet Earth.

According to a report released today by NOAA’s National Climatic Data Center, Earth’s combined average temperature for the year – over both land and sea surfaces – was 58.33°F.  That is 1.33°F above the 20th century average. It surpassed the previous annual record held by both 2005 and 2010 by 0.07°F.  2014 also marked the 38th consecutive year that our global temperature was above its long-term norm.

Rising ocean temperatures, according to NOAA, helped fuel this record warmth. The globally averaged sea surface temperature for 2014 was 1.03°F above the 20th century average of 60.9°F.  That is the highest on record, breaking the former record set in 1998 and tied in 2003 by 0.09°F.

It is interesting to note that ENSO-neutral conditions were present during all of 2014. That means El Niño, the warm phase of ENSO (El Niño-Southern Oscillation) did not influence this record warm year. Scientists, while acknowledging the decrease in the rate of warming over the past decade, say this fact undeniably confirms the continuation of global warming.

While heat dominated most of the planet in 2014, including parts of Alaska and the western United States, the eastern two-thirds of this country was one of the few cold pockets. Overall, the contiguous US experienced its 34th warmest year on record. This highlights the fact that climate change is a complex global phenomenon that involves much more than what is happening in our own backyards.

With records going back to 1880, nine of this planet’s top ten warmest years on record have all occurred since 2000. The only exception was 1998. As greenhouse gases – which drive our global temperature upward – are continuously emitted into the atmosphere, scientists say we can expect global temperatures to continue to rise and more warm records to be broken.

Credit: NOAA

Credit: NOAA

Credit: NOAA

Credit: NOAA

Warmest December on Record for Planet Earth

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Like most of the US, including here in NYC, temperatures across the globe soared last month.  In fact, December 2014 was Earth’s warmest December on record.

According to the latest report from NOAA’s National Climatic Data Center, the planet’s combined average temperature for the month – over both land and sea surfaces – was 55.39°F.  That is 1.39°F above the 20th century average. December 2014 also marked the 6th month this year to break a global temperature record.

The calendar year of 2014 (January – December), is now ranked as the warmest year on record for planet Earth. Global temperature records date back to 1880.

201412

Credit: NOAA

Warmest October on Record for Planet Earth

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Temperatures across the country and around the world soared last month. In fact, October 2014 was the 4th warmest October on record for the contiguous United States and the warmest ever recorded for the entire planet.

According to the latest global climate report released Thursday by NOAA’s National Climatic Data Center, Earth’s combined average temperature for the month – over both land and sea surfaces – was 58.43°F.  That is 1.33°F above the 20th century average. October 2014 also marked the 38th consecutive October that our global temperature was above its long-term norm and the 5th month this year to break a global temperature record.

Rising ocean temperatures, according to NOAA, helped fuel this record warmth. The global sea surface temperature for October was 1.12°F above the 20th century average of 60.6°F.  That is the highest on record for October and the sixth consecutive month to post a record high global sea surface temperature. Given all this warm water, it is interesting to note that El Niño conditions are not present in the Pacific.

Year to date, the first ten months of 2014 were the warmest of any year on record. Global temperature records date back to 1880.

Credit: NOAA

Credit: NOAA

Warmest September on Record for Planet Earth

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Temperatures across the globe soared last month. In fact, September 2014 was the warmest September ever recorded for the entire planet.

According to a report released Monday by NOAA’s National Climatic Data Center, Earth’s combined average temperature for the month – over both land and sea surfaces – was 60.3°F.  That is 1.3°F above the 20th century average. September 2014 also marked the 355th consecutive month that our global temperature was above its long-term norm.

This record warm September comes on the heels of the planet’s warmest summer and marks the fourth month this year to break a global temperature record. The other three months were May, June, and August. It is also interesting to note that all four of these monthly heat records occurred when El Niño conditions were not present in the Pacific.

Year to date, 2014 is now tied with 1998 for the warmest first nine months of the year on record. NOAA says, “If 2014 maintains this temperature departure from average for the remainder of the year, it will be the warmest year on record.”

The contiguous United States, by comparison, posted its coolest September in three years. This highlights the fact that climate change is a complex global phenomenon that involves much more than what is happening in our own backyards. Global temperature records date back to 1880.

Credit: NOAA

Credit: NOAA

Warmest August on Record for Planet Earth

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August was fairly seasonable in New York City this year. For the Earth as a whole, however, the average temperature soared to a record high yet again.

According to a report released this week by NOAA’s National Climatic Data Center, August 2014 was the warmest August ever recorded for the entire planet.  Earth’s combined average temperature for the month – over both land and sea surfaces – was 61.45°F. That is 1.35°F above the 20th century average. August 2014 also marked the 354th consecutive month that our global temperature was above its long-term norm.

Rising ocean temperatures, according to NOAA, helped fuel this record warmth. In fact, the August global sea surface temperature was 1.17°F above its long-term average of 61.4°F. That is the highest for any August on record and the highest departure from average for any month. The previous all-time record high was set just two months ago in June 2014.

Year to date, 2014 is currently the Earth’s third warmest year on record. Global temperature records date back to 1880.

Credit: NOAA/NCDC

Credit: NOAA/NCDC

An Increasing Number of 90° Days in NYC

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The summer of 2014, overall, was fairly mild in New York City. We only had 8 days reach 90°F or higher. On average, the city typically gets 15. That said, this was just one season. Looking at long-term trends, the number of 90°F days in the Big Apple has actually been increasing.

The graph below shows the number of 90-degree days recorded in Central Park by the National Weather Service every year from 1870 to 2013. While there has been variability over the years, the trend is clearly on the rise.

To date, the most 90°F days that NYC has ever had in one year was 39. That happened in both 1991 and 1993. On the opposite end of the spectrum, 1902 only had one day hit the 90° mark. Last summer, we made it to 90°F or higher 17 times.

Credit: The Weather Gamut

The number of 90-degree days recorded in Central Park by the NWS every year from 1870 to 2013.  Graph Credit: The Weather Gamut

The Weather of the Future: Forecast for September 2050

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In advance of the U.N. Climate Summit later this month, the World Meteorological Organization (WMO) has launched a video series of hypothetical weather forecasts for different regions of the globe that are all set 36 years in the future. They are meant to show that today’s climate projections could really be tomorrow’s weather. The U.S. version of this project was released today and it focuses on sea level rise, heat waves, drought, and the warming arctic.

Produced by the Weather Channel, the scenarios presented are based on projections published in the latest IPCC report and the U.S. National Climate Assessment. Watch the video below to see what an American weather forecast could look like on the not so distant date of September 23, 2050.

Video Credit: WMO, TWC, and YouTube

The Dew Point Makes a Difference

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“It’s not the heat, it’s the humidity.” This common refrain heard throughout much of the eastern U.S. in summer refers to how the amount of water vapor in the air affects human comfort. Since the main source of body cooling is evaporation of perspiration, the higher the moisture content of the air, the less evaporation takes place and the warmer we feel. One measure of atmospheric moisture is the dew point temperature.

The dew point, as defined by the NWS, is the temperature to which air must be cooled in order to reach saturation. In other words, the difference between the air temperature and the dew point temperature tells you how much moisture is in the air. The greater the distance between the two, the dryer the air is. Conversely, the closer they are together, the higher the moisture content of the air.

While everyone has a different tolerance for humidity, in summer – when air temperatures tend to be high – a dew point temperature of 50°F is generally considered comfortable. Dew points in the 60s are thought of as muggy and once they reach the 70s or higher, the air can feel down right oppressive. On the opposite end of the spectrum, dew points in the 40s or lower are considered dry. Dry air has its own set of comfort issues, including skin irritations.

September Brings NYC Warmest Day of the Year

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The summer months of June, July, and August have come and gone, but Tuesday brought New York City its hottest day of the year (so far). The high temperature in Central Park soared to 92°F.

According to the NWS, it was our warmest day since September 11, 2013 when the high was 96°F. The normal high in NYC at this time of year is 80°F.

Highlighting the relatively mild conditions that dominated this summer, Tuesday was also only the seventh time this season that the temperature reached 90°F or higher. The city, on average, typically sees fifteen 90-degree days per year.

Credit: The Weather Gamut

Credit: The Weather Gamut