Fall Foliage and Climate Change

Autumn is a season well known for its colorful foliage. Driven by the combination of sunlight, temperature, and precipitation, local displays vary from year to year. However, as the climate changes, so too will this familiar natural phenomenon.

As daylight hours decrease in the fall, there is less sunlight available to power photosynthesis – the chemical process that provides nutrients to trees by converting carbon dioxide and water into glucose, which is consumed by the tree and oxygen, which is released. This, in combination with falling temperatures, tells a tree to start preparing for winter.

To do this, a tree turns off its food producers by slowly corking the connection between leaf-stems and its branches.  This blocks the movement of sugars from the leaves to the tree as well as the flow of water from the roots to the leaves.  As a result, the leaves stop producing chlorophyll, the agent of photosynthesis and the reason for the green color of summer foliage.  As the green fades, other chemicals that have been present in the leaves all along begin to show.  These include xanthophyll and carotene, which produce yellow and orange leaves, respectively. Red to purplish colors are the result of anthocyanin, a chemical produced as a result any remaining sugars trapped in a leaf.

The change of leaf color happens every year, but the timing and duration of the displays are largely dependent on temperature and rainfall. Dry, sunny days and cool nights are the ideal recipe for beautiful fall foliage. Warmer and wetter conditions, on the other hand tend to delay the color change. However, extreme conditions, such as high heat, frost, excessive rain, or drought, can be a source of stress for trees and cause the colors to change early and the leaves to fall off faster.

As our climate changes, so too will displays of fall foliage. With warmer and wetter conditions forecast for the northeast, autumn colors are expected to peak later and disappear sooner. While there will still be variability from year to year, the fall foliage season in general is expected to get shorter. Furthermore, with the increasing probability of extreme weather events, such as storms with heavy rain, leaves could be swept from trees, effectively ending the season in a single day.

These changes will have more than an aesthetic affect. They are sure to have an impact on the multi-billion-dollar a year leaf-peeping ecotourism industry in several states.

Credit: Climate Central

September 2018: Earth’s Fourth Warmest September on Record

Our global temperature continued its upward trend last month with September 2018 tying 2017 as the fourth warmest September ever recorded on this planet.

According to the State of the Climate report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for the month – over both land and sea surfaces – was 60.4°F, which is 1.40°F above the 20th-century average. September also marked the 405th consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below average reading was December 1984.

While heat dominated most of the planet this September, some places were particularly warm, including much of Europe, Russia, the Middle East, and both the eastern and southwestern regions of the United States. For the contiguous US as a whole, September 2018 marked the fourth warmest September on record.

These soaring temperatures are largely attributed to the long-term trend of human-caused climate change. ENSO-neutral conditions prevailed in September, which means there was neither a warm El Niño nor a cool La Niña in the Pacific to influence global weather patterns.

Year to date, the first nine months of 2018 were the fourth warmest such period of any year on record. Global temperature records date back to 1880.

September 2018 was the planet’s 4th warmest September on record. Credit: NOAA

Special IPCC Report: Massive Global Effort Needed to Avoid Worst Climate Change Impacts

The UN’s Intergovernmental Panel on Climate Change (IPCC) released its Special Report on Global Warming of 1.5°C on Monday. It clearly states that the impacts of climate change will be greater at a lower degree of warming than previously thought.

Written by 91 scientists from 40 countries, the report finds that quick and dramatic action needs to be taken to avoid a warming increase of 1.5°C (2.7°F) above pre-industrial levels. Without aggressive cuts to global greenhouse gas emissions, the planet is expected to  reach this warming threshold between 2030 and 2052.

The Paris Agreement set the target of holding global warming to 2°C (3.6°F) above pre-industrial levels and urged countries to pursue an even tighter cap of 1.5°C (2.7°F) if possible. This more aggressive goal was added at the urging of officials from low-lying island nations – those most susceptible to sea level rise. As such, the IPCC began to look more closely at what 1.5°C (2.7°F) of warming would mean for people and ecosystems around the planet.

Previously, scientists thought that the most severe effects of climate change could be held off if the planet stayed below 2°C (3.6°F) of warming. However, this report shows that those impacts will come sooner, at the 1.5°C (2.7°F) mark. These consequences include coastal inundation from rising seas, worsening droughts and wildfires, as well as food shortages and mass die-offs of coral reefs. An extra half-degree Celsius, from 1.5°C to 2°C, would magnify those impacts.

To avoid the worst case of these types of effects, the report says the global economy needs to be transformed within the next few years. More specifically, greenhouse gas pollution must be reduced by 45% from 2010 levels by 2030, and 100% by 2050. While this is technically possible, the report also highlights it will require enormous political will.

Under the Paris Agreement, every country around the globe submitted individualized plans to reduce its greenhouse gas emissions known as nationally determined contributions (NDCs). While an important first step, these are not enough to meet the agreement’s 2°C (3.6°F) goal, to say nothing of the more aspirational target of 1.5°C (2.7°F).  In fact, they would allow for 3°C (5.4°F) of warming by the end of the century. However, the agreement does legally obligate countries to reconvene every five years to present updated plans spelling out how they will deepen their emissions cuts.

For the US, the second largest carbon polluter in the world after China, political will for climate action is something that is sorely lacking. President Trump announced plans to withdraw the US from the Paris Climate Agreement and has been rolling back his predecessor’s Clean Power Plan, the principle aspect of this country’s NDC.

Nonetheless, 2018 marks the halfway point between the passage of the Paris Climate Agreement in 2015 and the 2020 target for countries to begin ratcheting up their greenhouse gas cutting commitments. As such, this new report will be key to the discussions at the upcoming UN Climate Conference in Katowice, Poland this December.

Credit: Climate Matters

This Year’s “Climate Week NYC” Will Focus on Accelerating Climate Action

Climate Week NYC begins on Monday. This annual global summit takes place alongside the UN General Assembly and brings together leaders from a variety of sectors, including government, business, and non-profit organizations, to discuss solutions to climate change.

Organized by The Climate Group since 2009, the goal of the conference is to keep this pressing issue high on the global agenda. This year, which marks the halfway point between the passage of the Paris Climate Agreement in 2015 and the 2020 target for countries to ratchet up their greenhouse gas cutting commitments, the event will focus on ways to accelerate climate action. The ultimate goal of the non-binding Paris Accord is to limit global warming to 2°C (3.6°F) above pre-industrial levels

Public events to raise awareness and support of the summit’s mission are scheduled all week around the city, from September 24-30. They range in style from panel discussions and seminars to concerts and exhibitions. For the full program of events, go to the Climate Week website.

August 2018: Earth’s Fifth Warmest August on Record

Our global temperature continued its upward trend last month. August 2018 marked not only the fifth warmest August on record, but also closed out the planet’s fifth warmest June to August season – a period known as meteorological summer in the northern hemisphere.

According to the State of the Climate report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for August – over both land and sea surfaces – was 61.43°F, which is 1.33°F above the 20th-century average. This August also marked the 404th consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below average reading was December 1984.

Globally, the collective period of June, July, and August was also unusually warm. NOAA reports that Earth’s average temperature for the season was 1.33°F above the 20th century average of 60.1°F. That makes it the fifth warmest such period on record.

While heat dominated most of the planet during this three-month stretch, some places were particularly warm, including much of Europe, central Asia, and the southwestern United States. For the contiguous US as a whole, the season tied with 1934 as the fourth warmest summer on record.

These soaring temperatures are largely attributed to the long-term trend of human-caused climate change. ENSO-neutral conditions prevailed in August, which means there was neither a warm El Niño nor a cool La Niña in the Pacific to influence global weather patterns.

Year to date, the first eight months of 2018 were the fourth warmest such period of any year on record. Global temperature records date back to 1880.

Credit: NOAA

July 2018: Earth’s Fourth Warmest July on Record

Our global temperature continued its upward trend last month with July 2018 marking the fourth warmest July ever recorded on this planet. Only July 2015, 2016, and 2017 were warmer, with July 2016 holding the top spot.

According to the State of the Climate report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for July – over both land and sea surfaces – was 61.75°F, which is 1.35°F above the 20th-century average. July also marked the 403rd consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below average reading was December 1984.

While heat dominated most of the planet this July, some places were particularly warm, including much of Europe, Scandinavia, the western United States, and parts of southern Asia. For the contiguous US as a whole, July 2018 tied with 1998 as the eleventh warmest July on record.

These soaring temperatures are largely attributed to the long-term trend of human-caused climate change. ENSO-neutral conditions prevailed in July, which means there was neither a warm El Niño nor a cool La Niña in the Pacific to influence global weather patterns.

Year to date, the first seven months of 2018 were the fourth warmest such period of any year on record. Global temperature records date back to 1880.

July 2018 was the planet’s 4th warmest July on record. Credit: NOAA

June 2018: Earth’s Fifth Warmest June on Record

Our global temperature continued its upward trend last month with June 2018 marking the fifth warmest June ever recorded on this planet. The ten warmest Junes have all occurred since 2005, with 2016 earning the top spot.

According to the State of the Climate report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for June – over both land and sea surfaces – was 61.25°F, which is 1.35°F above the 20th-century average. June also marked the 402nd consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below average reading was December 1984.

While heat dominated most of the planet this June, some places were particularly warm, including much of Europe, central Asia, and parts of the Middle East. Here in the contiguous US, it was our third warmest June on record.

These soaring temperatures are largely attributed to the long-term trend of human-caused climate change. ENSO-neutral conditions prevailed in June, which means there was neither an El Niño nor a La Niña in the Pacific to influence global weather patterns.

Year to date, the first six months of 2018 were the fourth warmest such period of any year on record. Global temperature records date back to 1880.

June 2018 was the planet’s 5th warmest June on record. Credit: NOAA

May 2018: Earth’s Fourth Warmest May on Record

Our global temperature continued its upward trend last month. May 2018 marked not only the fourth warmest May on record, but also closed out the planet’s fourth warmest March to May season, known as meteorological spring in the northern hemisphere.

According to the State of the Climate report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for May – over both land and sea surfaces – was 60.04°F, which is 1.44°F above the 20th-century average. The years 2014-2018 now rank among the five warmest Mays on record.

This May also marked the 401st consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below average reading was December 1984.

While heat dominated most of the planet this May, some places were particularly warm, including much of Europe and North America. Here in the contiguous US, it was our warmest May ever recorded. The previous record had been in place since 1934.

Globally, the three-month period of March, April, and May was also unusually warm. NOAA reports that Earth’s average temperature for the season was 1.48°F above the 20th century average of 56.7°F. That makes it the fourth warmest such period on record.

These soaring temperatures are largely attributed to the long-term trend of human-caused climate change. ENSO-neutral conditions prevailed in May, which means there was neither an El Niño nor a La Niña in the Pacific to influence global weather patterns.

Year to date, the first five months of 2018 tied 2010 as the fourth warmest such period of any year on record. Global temperature records date back to 1880.

May 2018 was the fourth warmest May ever recorded on Earth. Credit: NOAA

Storm King Art Center Exhibition Focuses on Climate Change

Art and science have come together to expand the public conversation on climate change  at Storm King Art Center in Orange County, NY. In an exhibition called Indicators: Artists on Climate Change, the work of seventeen artists and collectives address the diverse impacts of this critical issue.

Curated by Nora Lawrence, the exhibit is a mix of large-scale sculptures and installations spread out across the open air museum’s five-hundred acres as well as smaller pieces displayed in an indoor gallery.

Credit: Mary Mattingly/Storm King

Notable among the various projects is Mary Mattingly’s installation, Along the Lines of Displacement: A Tropical Food Forest. This stand of palm trees imported from Florida offers visitors a glimpse of what the landscape of upstate New York might look by the end of the century when the average temperature is expected to increase by 7.2°F (4°C) if global warming continues unabated.

Credit: Justin Brice Guarigila/Storm King

Another piece that stands out in Storm King’s bucolic setting is Justin Brice Guarigila’s We Are the Asteroid.  The orange colored, solar-powered LED highway message sign – the sort usually seen flashing information about dangerous situations – displays three-line ecological aphorisms by philosopher Timothy Morton. These include the piece’s moniker as well as things like “Danger: Anthropocentrism” and “Warning: Hurricane Human”.

Credit: Hara Woltz/Storm King

Embracing the science of climate change is Hara Woltz’s “Vital Signs”. In this interactive piece, a working weather station is encircled  by nine cylinders (a reference to the shape of ice-core tubes) that present the idea of albedo and melting sea ice. The top of each cylinder gets darker as a viewer moves around the circle. More specifically, the lighter area decreases by 13% per cylinder reflecting the predicted decrease in Arctic sea ice per decade relative to the 1981-2010 average. The cylinders also progressively get taller, referencing sea level rise. Data from the weather station is displayed in real time on Storm King’s website.

Other exhibiting artists include David Brooks, Dear Climate, Mark Dion, Ellie Ga, Allison Janae Hamilton, Jenny Kendler, Maya Lin, Alan Michelson, Mike Nelson, Steve Rowell, Gabriela Salazar, Rebecca Smith, Tavares Strachan, and Meg Webster.

The exhibit is on view through November 11, 2018.

Catastrophic Flooding Hits Ellicott City Twice in Two Years

For the second time in less than two years, heavy rain unleashed catastrophic flooding in Ellicott City, Maryland this Sunday.

According to the NWS, the area received between 8 and 12 inches of rain in less than four hours. On average, the area gets 4 inches of rain for the entire month of May. This massive amount of precipitation in such a short period overwhelmed streams throughout the region and turned Ellicott City’s historic Main Street into a raging river. The floodwater, which reached as high as the second floor of most buildings, damaged or destroyed numerous businesses and swept away dozens of cars and trees. Local officials say that one man, a sergeant with the National Guard, was killed while trying to rescue people from the fast flowing water.

This type of rainfall is considered a one in one thousand year event. However, that does not mean it can only happen once every thousand years. It is the recurrence interval, a statistical calculation that means an event has a one in one thousand chance (0.1%) of happening in any given year in a given location. Ellicott City experienced an eerily similar event in July 2016.

There were several drivers behind this deadly deluge. First, “training” thunderstorms developed along a stationary front. This is a situation where strong thunderstorms continuously form over the same area – like train cars traveling along a track – dumping excessive amounts of rain.

Although climate change did not cause these storms, it has altered the environment in which they form and is making them more common. As greenhouse gases warm the atmosphere, the air is able to hold more water vapor. More specifically, according to the Clausius–Clapeyron relation, for every increase of 1°F, the saturation level of the atmosphere increases by about 4%. That means there is more evaporation from oceans, rivers, and lakes, and therefore more water vapor available to condense and fall as precipitation.

Another major player in Sunday’s flood was the area’s topography. Founded as a gristmill town in 1772, Ellicott City sits in a valley surrounded by several streams that feed into the Patapsco River. Just ten miles outside of Baltimore, it is a highly urbanized area with extensive amounts concrete and asphalt. These impervious surfaces leave the rainwater with no place to go but racing downhill and through the town.

All of these factors will have to be considered as Ellicott City decides how to rebuild for the second time in two years.

Torrential rain turned Main Street in Ellicott City, MD into a raging river. Credit: S. Baranoski