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.

Survey Says… Art Can Help Broaden the Public Conversation on Climate Change

The 97th Annual Meeting of the American Meteorological Society is taking place this week in Seattle and I will be presenting a poster titled “Art Can Help Broaden the Public Conversation on Climate Change.”

Building on my talk, The Art and Science of Climate Change, I was curious to know if climate-art was influencing people’s opinions. Therefore, moving from the qualitative to the quantitative, I conducted a national poll using Survey Monkey. Participants were asked comparison questions about the influence of traditional graphs vs. artistic interpretations of climate change. The graphs were sourced from the IPCC’s fifth assessment report and the artwork came from both photojournalists and conceptual artists.

When compared to a graph, the different styles of art received different reactions. On average, however, a significant number of the participants (34%) related more to the issues of climate change via art than through traditional charts and graphs. Overall, 64% of participants said art had changed the way they thought about a subject in the past.

These results show art to be a powerful tool of communication that helps to broaden the public conversation on climate change. They also highlight the fact that a variety of visual outreach methods are needed to reach the entire population on this critical issue that affects us all in one way or another.

Climate-Art Survey shows that art can help broaden the public conversation on climate change. Credit: The Weather Gamut.

Sea Level Rise Projections Revised Upward

Citing rapid melting at the poles, NOAA says global sea levels will rise faster than previously projected. This increases the flood risk for many coastal communities in the United States.

The agency’s new report, “Global and Regional Sea Level Rise Scenarios for the US”, updates a 2012 study and outlines a range of possible situations. Through 2100, it projects a global sea level rise of at least 1 foot on the low end to as high as 8 feet under a worst case scenario. The previous projections were estimated to be 4 inches and 6.6 feet, respectively.

On a regional level, from Virginia to Maine, sea-level rise is expected to be 1 to 1.6 feet greater than the global average. This is because the land is slowly sinking at the same time the water is rising. This precarious combination will intensify both high tide flooding and any storm surge events in the region.

The two main drivers of sea level rise are thermal expansion – a process in which water expands as it warms – and the melting of land-based ice. Both are the result of rising global temperatures.

The exact amount of sea level rise will depend on how much greenhouse gases are added to the atmosphere in the near future and the rate at which the massive ice sheets in Greenland and Antarctica melt.

Relative sea level trends based upon full record (>30-year period of record in all cases) measured and published for NOAA tide gauges through 2015. Credit: NOAA

2016: Earth’s Third Consecutive Warmest Year on Record

It’s official, 2016 was the warmest year ever recorded on this planet.

According to a report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for the year – over both land and sea surfaces – was 58.69°F. That is a staggering 1.69°F above the 20th-century average and surpasses the previous annual record that was set just last year. That makes 2016 the third year in a row to break a global temperature record.

As remarkable as this feat is, it does not come as much of a surprise. During the year, eight new global monthly temperature records were set.

A strong El Niño event influenced this record warmth, but it does not tell the whole story as it dissipated in June and was replaced by its cooler counterpart, La Niña, in the autumn. Therefore, the long-term trend of human-caused climate change was also a key factor. NOAA reports that 2016 marked the 40th consecutive year that our annual global temperature was above its long-term norm.

While heat dominated the planet last year, some places were particularly warm. Here in the contiguous US, it was our second warmest year on record.

Looking at the bigger picture, all sixteen years of this century rank among the seventeen warmest ever recorded and five were record breakers (2005, 2010, 2014, 2015, and 2016). As greenhouse gases – the main drivers of global warming – continue to spew into the atmosphere, temperatures will continue to rise and records will likely continue to fall. Global temperature records date back to 1880.

2016 was Earth’s third consecutive warmest year on record. Credit: NOAA

A Look at Why Death Valley is the Hottest, Driest, and Lowest Place in US

Death Valley National Park is famous for being the hottest, driest, and lowest place in the United States. The interesting thing about all these extremes, as I learned during a recent visit, is how they interconnect.

Situated in eastern California near the Nevada border, the park’s topography is known as basin and range. This is where the earth’s crust is rifting apart, creating mountains in some areas and deep basins in others. Death Valley is a long, narrow basin that reaches a depth of 282 feet below sea level. It is also in the rain shadow of four different mountain ranges to the west – the Coastal Range, the Sierra Nevada, the Argus Range, and the Panamint Range.

As storms move inland from the Pacific, they must rise up and over each range. In doing so, they cool and their water vapor condenses into rain or snow that falls on the western side of these mountains. By the time a storm system reaches Death Valley, it has lost most of its moisture. The average annual rainfall in the park, according to NOAA, is just 2.36 inches.

These dry conditions, along with the valley’s below-sea-level elevation, help to produce the park’s famous heat. With cloud free skies and sparse vegetation, a maximum amount of sunlight can reach the ground. The rocks and parched soil absorb the heat and radiate it into the air. The warm air rises but becomes trapped by the steep valley walls. After cooling slightly, it is recycled back toward the valley floor where it is heated even further by atmospheric compression. During the summer months, this process generates hot winds and sizzling temperatures. The average high temperature in the park ranges from 67°F in January to 116°F in July. The hottest temperature ever recorded was 134°F on July 10, 1913 – a world record.

Looking ahead, as the climate changes, the southwestern region of the US is expected to become even hotter and drier. It seems like only a matter of time before Death Valley breaks its own heat record.

At 282 feet below sea level, Basin in Death Valley National Park is the lowest point in the US. Credit: Melissa Fleming

A Record Warm January Day in NYC

The calendar says January, but it felt more like April in New York City on Thursday. The temperature soared to 66°F in Central Park, setting a new record high for the date. The previous record of 64°F stood since 1890. The overnight low temperature of 47°F was also record warm.

The city’s normal high this time of year is 38°F, but a “January thaw” is not unusual. Nevertheless, after getting 6.3 inches of snow over the weekend and temperatures only reaching the mid-20s on Monday, these spring-like conditions felt like weather whiplash.

Many New Yorkers enjoyed the unseasonable warmth, while others were sad to see the snow melt away. It is, however, still January. So, regardless of opinions, keep your winter gear handy.

January 12th brought NYC a record high temperature and a record warm low temperature. Credit: The Weather Gamut

Intense Rain Puts a Big Dent in California’s Drought

Over the past week, a cavalcade of intense rain and snowstorms battered the west coast of the US and put a major dent in California’s five-year drought.

According to the latest report from the US Drought Monitor, the northern third of the Golden State is now drought free. This is a major change from just three months ago, when the entire state was in some form of drought.

Across the region, copious amounts of precipitation were reported. More than a foot of rain fell in the Sierra Nevada, with 20.7 inches measured locally at Strawberry Valley, CA. Higher elevations saw tremendous snowfall totals. Heavenly Ski resort in South Lake Tahoe, according to the NWS, received an incredible 12 feet of snow in just one week.

These staggering totals came courtesy of a weather phenomenon known as an “atmospheric river”. These are narrow, but intense bands of water vapor sourced from the tropics. Often originating near Hawaii, this fire hose of moisture is sometimes called a “pineapple express.”

While this excessive rainfall did cause flooding events across the region, reservoir levels have benefited. Lake Shasta, the largest largest reservoir in California, is currently at 81% of total capacity and 126% of its historical average for the date.

Southern California also picked up some much-needed rainfall, but still remains in drought. That said, only 2% of the state is currently in exceptional drought, the worst possible category.

Northern California is drought free for the first time in five years. Credit: US Drought Monitor

Weather Lingo: Rain Shadow

The world of weather has some interesting words and phrases. One of these is “Rain Shadow”.

While it sounds rather poetic, a rain shadow refers to the land area on the leeside of a mountain that is exceptionally dry. Mountains act as barriers for weather systems traveling in a region’s prevailing winds, forcing them to drop most of their moisture on the windward side before they can pass.

As an air mass rises up and over a mountain, it enters an area of lower atmospheric pressure where it expands and cools. As a result, the moisture it contains condenses, clouds form, and precipitation falls. After the air mass moves over the mountain, it starts to descend the other side. The air is warmed by compression and the clouds dissipate. This means little to no rain falls on the leeward side.

Rain shadows are found all over the world, from the Tibetan Plateau in Asia to the Atacama Desert in South America. Here in the US, Death Valley is a famous example as it lies in the rain shadow of four different mountain ranges.

The Rain Shadow Effect. Credit: Kagee Commons

2016 was Second Warmest Year on Record for US

2016 was the second-warmest year ever recorded in the continental US.

The average annual temperature of the lower 48 states, according to NOAA’s National Centers of Environmental Information, was 54.9°F. That is a whopping 2.9°F above the 20th century average and only 0.4°F shy of the record that was set in 2012. This also marks the 20th consecutive year that the annual average temperature for the contiguous US was above its long-term norm.

From coast to coast, every state posted one of their top-seven warmest years. Georgia was record warm and Alaska, the nation’s northern most state, had its third consecutive warmest year on record. “The breadth of the 2016 warmth is unparalleled in the nation’s climate history,” NOAA said. “No other year had as many states breaking or close to breaking their warmest annual average temperature.”

Credit: NOAA

2016 was also notable for its unusual number of weather and climate disasters that each totaled more than $1 billion in damages. In all, fifteen such events collectively caused $46 billion in direct costs and claimed the live of 138 people across the US. These incidents included drought, wildfire, four inland floods, eight severe storms, and a tropical cyclone. Only 2011, with sixteen events, produced more billion-dollar disasters.

Credit: NOAA

The exceptional warmth of 2016 was driven by a combination of strong El Niño conditions at the beginning of the year and the long-term trend of human-caused climate change. These soaring temperatures, however, were not limited to US borders. Later this month, NOAA is expected to announce that 2016 was the planet’s warmest year on record for the third year in a row.

Weather records for the contiguous United States date back to 1895.

2016 Ties for 3rd Warmest Year on Record in NYC

New York City experienced some noteworthy weather in 2016, especially swinging between the extremes of record cold and record warmth. In the end, however, the warmth won out. The city’s average annual temperature in Central Park was 57.2°F, which is 2.2°F above normal. That means 2016 tied 1998 for NYC’s third warmest year on record!

With a strong El Niño in place at the beginning of the year, the city experienced its second warmest winter ever recorded. That said, a number of arctic outbreaks sent temperatures plummeting a few times throughout the season. The coldest day of the year came on February 14 when the temperature dropped to -1°F – a new record low for the date.

When summer rolled around, it brought the city a number of very hot and humid days. The city typically sees 15 days per year with temperatures in the 90s, but 2016 produced a sweltering 22. The hottest day came on August 13 when the mercury soared to 96°F in Central Park. When humidity was factored in, the heat index or real feel temperature was in the triple digits.

While El Niño gave readings a boost early in the year, it dissipated in spring and was replaced by its cooler sister, La Niña. Nonetheless, every month of 2016 posted an above average temperature in NYC.

Precipitation was also erratic. While there were a number of heavy rain events, including some that broke daily rainfall records such as the 2.22 inches that came down on November 29, the city was mostly dry. Overall, NYC received 42.17 inches of rain in Central Park for the entire year. That is 7.77 inches below normal. This dearth of rain caused moderate to severe drought conditions across the city.

Snowfall, ironically, was abundant. During one of the year’s arctic blasts, a large amount of moisture was also in place to produce a major show event. Dubbed the “Blizzard of 2016”, this one storm dumped 27.5 inches of snow on the city. It was the Big Apple’s biggest snowstorm on record. For the calendar year as a whole, the city accumulated 35.3 inches of snow, which is 9.5 inches above average.

Records for the Central Park Climate Station date back to 1873.

Every month of 2016 posted an above average temperature in NYC. Credit: The Weather Gamut

Only four months of 2016 produced average to above average rainfall in NYC. Credit: The Weather Gamut