Hurricane Irma Challenges Multiple Records

Hurricane Irma’s final chapters have yet to be written, but the storm has already earned its place in the history books.

According to NOAA, Irma’s winds peaked at 185 mph. That means it is tied as the second strongest hurricane ever recorded in the Atlantic Basin. It shares this dubious honor with the Labor Day /Florida Keys Hurricane of 1935, Hurricane Gilbert of 1988, and Hurricane Wilma of 2005. Only Hurricane Allen in 1980 was stronger with winds clocked at 190 mph. That said, Irma now ranks as the strongest storm on record in the Atlantic outside of the Carribean Sea and the Gulf of Mexico.

Irma’s winds remained at 185 mph for 37 hours. That is the longest any storm on the planet has maintained that level of intensity. The previous record of 24 hours was set by Super Typhoon Haiyan in the northwest Pacific in 2013. Furthermore, Irma remained a Category 5 hurricane for three consecutive days, the longest such measurement since the satellite era began in 1966.

Source: NHC

Weather History: Ten Year Anniversary of NYC’s Strongest Tornado

Ten years ago today, an EF2 tornado roared through New York City. It was the strongest twister on record to hit the Big Apple.

NYC Tornado of 2007. Credit: NYT

With winds measured up to 135 mph, it left a trail of destruction nine miles long from Staten Island to Brooklyn with the hardest hit neighborhoods being Bay Ridge and Sunset Park. The storm toppled trees and knocked out power to more than 4,000 customers. It damaged hundreds of cars and dozens of homes, including five that had their roofs ripped off. The storm also dumped 1.91 inches of rain in just one hour, which caused flash floods and the temporary suspension of subway service during the morning commute.

Historically, tornadoes have been rare events in NYC. In recent years, however, they have been happening more frequently. Of the eleven twisters that have touched down in the city since 1950, seven have occurred since 2003.

Note: Tornado ratings moved from the Fujita Scale (F) to the Enhanced Fujita Scale (EF) in 2007.

A Brief History of How We Know CO2 Drives Climate Change

The US Energy Secretary, Rick Perry, recently denied that CO2 is the main driver behind our changing climate. Nominated by President Trump, his comments are in line with the Administration’s rollback of the Clean Power Plan and withdrawal from the Paris Climate Agreement. The fact is, however, the scientific fundamentals of the greenhouse effect have been understood since the 1800s.

One of the first scientists to look into the planet’s energy balance was Joseph Fourier, a French physicist, in the 1820s. Given the Earth’s distance from the Sun, he was curious to know why its temperature was not cooler. Fourier felt that something other than incoming solar radiation was keeping the planet warm and hypothesized that the atmosphere was somehow acting like an insulating blanket. Working with the limited technology of the day, however, he was unable to make the detailed measurements needed to carry his idea further.

Decades later, in the 1860s, an Irish scientist named John Tyndall picked up Fourier’s theory. An alpine adventurer, he was interested in glaciers and the then controversial idea of ice ages. Wanting to know more about how they formed, he devised an experiment to see if the Earth’s atmosphere was acting like a thermostat. For this, he built a spectrophotometer – an instrument that measures the amount of heat that gases can absorb. His experiments showed that water vapor, carbon dioxide (CO2), and methane were all very efficient at trapping heat. This essentially proved Fourier’s idea of a greenhouse effect.

In the 1890s, Svante Arrhenius, a Swedish physicist, followed up on Tyndall’s idea of an atmospheric thermostat and ran with it. Ruling out water vapor as too transitory, he focused on carbon dioxide, which tends to linger in the atmosphere for a long time. His calculations showed that doubling the amount of carbon dioxide in the atmosphere would raise the average global temperature by 5°C (9°F).

To understand if such a large-scale change in atmospheric CO2 was possible, he turned to Arvid Hogbom, a colleague studying the global carbon cycle. This is the natural geochemical process where volcanic eruptions and the chemical weathering of rocks release CO2, while plants and oceans absorb it. Hogbom confirmed that CO2 levels could change dramatically over long periods of time. However, he also noted that industrial processes were releasing a significant amount of CO2 relatively quickly. Using this information, Arrhenius calculated that human activities, such as burning fossil fuels, could alter the composition of the atmosphere and increase global temperatures. In the 1890’s, however, fossil fuel use was only a fraction of what it is today and he believed it would take more than 1,000 years for the level of atmospheric CO2 to double.

Jumping ahead to the 1950s, Charles David Keeling, a researcher at the Scripps Institution of Oceanography in California, found a way to directly monitor levels of CO2 in the atmosphere. He created an instrument called a gas chromatograph and installed it on top of Mauna Loa in Hawaii. At an elevation of more than 11,000 feet in the middle of the Pacific Ocean, it is removed from both direct CO2 sources like factories and sinks such as forests that could skew the data. Still in operation today, the information recorded at this station is known as the Keeling Curve. It shows the steady increase in CO2 levels in the atmosphere from 1958 to present.

Keeling’s measurements provided solid evidence that CO2 levels were rising and validated the theories of Tyndall and Arrhenius. More recently, scientists were able to extend his curve back in time by analyzing ancient air bubbles trapped in ice cores from Greenland and Antarctica. This lengthy record shows that pre-industrial CO2 levels in the atmosphere were about 280 ppm. Today, they are over 400ppm – the highest they have been in more than 800,000 years.

Seeing this dramatic rise in CO2 and realizing the impact that a warming climate could have on society, the UN formed the Intergovernmental Panel on Climate Change (IPCC) in 1988. They assess the peer-reviewed research of thousands of scientists from around the world and publish a synthesized view of the current state of the science. The latest IPCC report (AR5 published in sections in 2013/2014) unconditionally states that human activities are the main drivers of modern climate change.

Therefore, while it is the nature of all science to evolve with time and research, it is safe to say that role of CO2 does not require further debate. Today, the impacts of different feedback loops within the climate system are an active area of investigation. Science is following the evidence and moving ahead. Politics needs to catch up.

Scientists have been studying the climate since the 1800s.

As CO2 levels go up, so does the temperature. Credit: Climate Central

Thomas Jefferson and the Weather in Philadelphia on July 4, 1776

Thomas Jefferson is well known as one of the Founding Fathers of the United States, but he was also an astute and systematic weather observer.

Portrait of Thomas Jefferson by Rembrandt Peale, 1805. Credit: NYHS

In the summer of 1776, Jefferson was in Philadelphia, PA to sign the Declaration of Independence.  While there, he purchased a thermometer and a barometer – new and expensive weather equipment at that time. For the next 50 years, he kept a meticulous weather journal.  He recorded daily temperature data wherever he was – at home in Virginia or while traveling.

On July 4, 1776, Jefferson noted that the weather conditions in Philadelphia were cloudy with a high temperature of 76°F.

In an effort to understand the bigger picture of climate in America, Jefferson established a small network of fellow observers around Virginia as well as contacts in a few other states. According to records at Monticello, he hoped to establish a national network for weather observations. While this plan did not come to fruition during his lifetime, today’s National Weather Service considers him the “father of weather observers.”

Happy Independence Day!

An excerpt from Thomas Jefferson’s Weather Journal, July 1776. Credit: NCDC

What are the Dog Days of Summer?

The “Dog Days” of summer have arrived. This popular saying refers to what are traditionally the hottest and most oppressive days of the season.

Rooted in astronomy, the phrase is linked to Sirius, the brightest star seen from Earth. As part of the constellation Canis Major, it is known as the Dog Star.  During most of July and August, Sirius rises and sets with our Sun. Ancient Greeks and Romans believed it acted like a second Sun, adding extra heat to summer days. Today, we know that light from this distant star does not affect our weather, but the name has endured.

Varying by latitude around the globe, the so-called “Dog Days” of summer typically run from July 3 to August 11 in the United States.

Sirius, the “Dog Star”.  Credit: EarthSky/Tom Wildoner

Love of Winter

Today is Valentine’s Day, a holiday when images of cupid and hearts abound. But for me, it is George Bellows’ Love of Winter that always comes to mind as we mark the mid-point of what is usually New York City’s snowiest month of the year.

A longtime personal favorite, this 1914 painting captures the spirit of those who embrace the season. Filled with the blurred movement of skaters on a frozen pond and accented with spots of bright color that pop against the snow, it conveys the joy of being out in nature on a cold winter day.

While Bellows is better known for depicting scenes of boxing matches and urban life, art historians say he enjoyed the challenge of painting the varied lighting conditions produced by a snow-covered landscape. In fact, he wrote a letter to a friend in January 1914 complaining about the lack of snow in NYC that winter. He said, “There has been none of my favorite snow. I must paint the snow at least once a year.” Then, about a month later, his wish for snow was granted and this picture was created.

Love of Winter is part of the Friends of American Art Collection at the Art Institute of Chicago.

“Love of Winter”, 1914 by George Bellows. Collection of the Art Institute of Chicago

Why Today is National Weatherperson’s Day

Today is National Weatherperson’s Day in the United States. While not an official federal holiday, it is a day to recognize the work of all individuals involved in the field of meteorology – not just prognosticating groundhogs.

According to the NWS, today’s designation honors the birthday of Dr. John Jeffries who was one of America’s first weather observers. Born in 1744, this Boston-based physician had a deep interest in weather and kept detailed records of daily conditions from 1774 to 1816. He also took the first known upper air observations from a hot air balloon in 1784.

Since the 18th century, the weather industry has grown by leaps and bounds. Utilizing radar, satellites, and computer models, meteorologists today provide forecasts and warnings to the public in an effort to protect lives and property. But in the end, weatherpersons, like Dr. Jeffries, are fascinated by weather and are always seeking to improve their understanding of its complex processes.

Dr. John Jeffries taking weather measurements from a hot air balloon. Source: Wonderful Balloon Ascents.

Climate Science is Not New

As someone who both writes and gives talks on climate change, I often meet people with doubts about the subject who ask: “Climate science is so new, how can we trust it?” The answer is simple. It is not new. In fact, the fundamentals of climate science have been understood for close to 200 years.

One of the first scientists to look into the planet’s energy balance was Joseph Fourier, a French physicist, in the 1820s. Given the Earth’s distance from the Sun, he was curious to know why its temperature was not cooler. Fourier felt that something other than incoming solar radiation was keeping the planet warm and hypothesized that the atmosphere was somehow acting like an insulating blanket. Working with the limited technology of the day, however, he was unable to make the detailed measurements needed to carry his idea further.

Decades later, in the 1860s, an Irish scientist named John Tyndall picked up Fourier’s theory. An alpine adventurer, he was interested in glaciers and the then controversial idea of ice ages. Wanting to know more about how they formed, he devised an experiment to see if the Earth’s atmosphere was acting like a thermostat. For this, he built a spectrophotometer – an instrument that measures the amount of heat that gases can absorb. His experiments showed that water vapor, carbon dioxide (CO2), and methane were all very efficient at trapping heat. This essentially proved Fourier’s idea of a greenhouse effect.

In the 1890s, Svante Arrhenius, a Swedish physicist, followed up on Tyndall’s idea of an atmospheric thermostat and ran with it. Ruling out water vapor as too transitory, he focused on carbon dioxide, which tends to linger in the atmosphere for a long time. His calculations showed that doubling the amount of carbon dioxide in the atmosphere would raise the average global temperature by 5°C (9°F).

To understand if such a large-scale change in atmospheric CO2 was possible, he turned to Arvid Hogbom, a colleague studying the global carbon cycle. This is the natural geochemical process where volcanic eruptions and the chemical weathering of rocks release CO2, while plants and oceans absorb it. Hogbom confirmed that CO2 levels could change dramatically over long periods of time. However, he also noted that industrial processes were releasing a significant amount of CO2 relatively quickly. Using this information, Arrhenius calculated that human activities, such as burning fossil fuels, could alter the composition of the atmosphere and increase global temperatures. In the 1890’s, however, fossil fuel use was only a fraction of what it is today and he believed it would take more than 1,000 years for the level of atmospheric CO2 to double.

Jumping ahead to the 1950s, Charles David Keeling, a researcher at the Scripps Institution of Oceanography in California, found a way to directly monitor levels of CO2 in the atmosphere. He created an instrument called a gas chromatograph and installed it on top of Mauna Loa in Hawaii. At an elevation of more than 11,000 feet in the middle of the Pacific Ocean, it is removed from both direct CO2 sources like factories and sinks such as forests that could skew the data. Still in operation today, the information recorded at this station is known as the Keeling Curve. It shows the steady increase in CO2 levels in the atmosphere from 1958 to present.

Keeling’s measurements provided solid evidence that CO2 levels were rising and validated the theories of Tyndall and Arrhenius. More recently, scientists were able to extend his curve back in time by analyzing ancient air bubbles trapped in ice-cores from Greenland and Antarctica. This lengthy record shows that pre-industrial CO2 levels in the atmosphere were about 280 ppm. Today, they are over 400ppm – the highest they have been in more than 800,000 years.

Seeing this dramatic rise in CO2 and realizing the impact that a warming climate could have on society, the UN formed the Intergovernmental Panel on Climate Change (IPCC) in 1988. They assess the peer-reviewed research of thousands of scientists from around the world and publish a synthesized view of the current science. The latest IPCC report (AR5 published in sections in 2013/2014) unconditionally states that human activities are the main drivers of modern climate change.

Therefore, while it is the nature of all science to evolve with time and research, it is safe to say that climate science is not a new subject. It is only relatively new to those in the political sphere.

Giants in the history of climate science.

Weather and the Macy’s Thanksgiving Day Parade

The Macy’s Thanksgiving Day Parade is a long-standing holiday tradition in New York City.  For 90 years, it has marched rain or shine. Nevertheless, the weather has been a factor for the event several times over the years.

Famous for its giant character balloons, high winds are the main weather challenge for the parade. According to city guidelines, the multi-story balloons cannot fly if there are sustained winds in excess of 23 mph or gusts higher than 34 mph. These regulations were put in place following a 1997 incident where gusty winds sent the “Cat in the Hat” balloon careening into a light post, which caused debris to fall on spectators.

The only time the balloons were grounded for the entire parade was in 1971 when torrential rain swept across the city. In 1989, a snowstorm brought the Big Apple a white Thanksgiving with 4.7 inches of snow measured in Central Park. The parade marched on that year, but without the “Snoopy” and “Bugs Bunny” balloons as they were damaged by high winds earlier that morning.

This year, the wind is not expected to be a problem. Temperatures, however, are forecast to be a bit chilly – mostly in the mid-40s.  So, bundle up if you are planning to watch the parade in person.

Marching from West 77th Street to West 34th Street in Manhattan, the 90th Annual Macy’s Thanksgiving Day Parade is scheduled to begin at 9 AM on Thursday morning.

Happy Thanksgiving!

Paddington Bear Balloon floats down 6th Ave in Macy's Thanksgiving Day Parade.  Credit: Macy's

Paddington Bear Balloon floats down 6th Ave in Macy’s Thanksgiving Day Parade. Credit: Macy’s

200th Anniversary of the ‘Year Without a Summer’

Two hundred years ago, the warm weather we typically associate with summer never materialized for large areas of the globe, including the eastern United States and Europe. As a result, 1816 has become known as the year without a summer.

This historic cold spell was caused by the eruption of Indonesia’s Mount Tambora in April 1815 – the most powerful volcanic eruption ever recorded. While it devastated the immediate area and unleashed a deadly tsunami, it was the the massive amounts of sulfur dioxide spewed out by the volcano that had far-reaching impacts on the global climate.

After an eruption, ash and debris can cool a region for a few days by blocking out the sun. However, extremely powerful eruptions – like Tambora – can send gas clouds into the stratosphere – an altitude above where our daily weather takes place. The stability of this layer of the atmosphere means the sulfur dioxide can linger there for several months. Moving around the globe easily at this level, the sulfur dioxide spreads out, reacts with water vapor, and forms sulfate aerosols. These reflect incoming solar radiation and increase the reflectivity of clouds, cooling surface temperatures.

The average global temperature in 1816, according to the UCAR, dropped 3°C. That may sound like a small number, but it had dramatic impacts, especially during the summer months. In the US, heavy snow blanketed parts of New England in June. Frost was reported as far south as Virginia through July. Then in August, after a brief reprieve, severe frost returned to many parts of the northeast. These unseasonable conditions caused widespread crop failures, livestock losses, famine, and disease. Ultimately, it forced many people to migrate west.

Europe suffered similar conditions, but also had excessive rainfall. Crop failures and price inflation for basic goods from Ireland to Germany lead to food riots in many cities. The gloomy weather also famously inspired many British and European writers. Mary Shelly, for example wrote Frankenstein while on vacation at Lake Geneva in Switzerland that summer.

Luckily, this dramatic – albeit natural – climate change was temporary. The aerosols eventually settled out of the atmosphere and sunlight returned. While the process that produced this moment in weather history was essentially the opposite of the runaway green house effect happening today, it is a great example of how sensitive the climate is to changes in atmospheric composition. It also shows how seemingly small changes in global temperature can have huge impacts on our lives.