Before climate change thawed the winters of New Jersey, this lake hosted boisterous wintertime carnivals. As many as 15,000 skaters took part, and automobile owners would drive onto the thick ice. Thousands watched as local hockey clubs battled one another and the Skate Sailing Association of America held competitions, including one in 1926 that featured 21 iceboats on blades that sailed over a three-mile course.
In those days before widespread refrigeration, workers flocked here to harvest ice. They would carve blocks as much as two feet thick, float them to giant ice houses, sprinkle them with sawdust and load them onto rail cars bound for ice boxes in New York City and beyond.
New Jersey’s average temperatures have risen nearly 2 degrees Celsius since 1895 — double the average for the Lower 48 states. “These winters do not exist anymore,” says Marty Kane, a lawyer and head of the Lake Hopatcong Foundation.
That’s because a century of climbing temperatures has changed the character of the Garden State. The massive ice industry and skate sailing association are but black-and-white photographs at the local museum. And even the hardy souls who still try to take part in ice fishing contests here have had to cancel 11 of the past dozen competitions for fear of straying onto perilously thin ice and tumbling into the frigid water.
New Jersey may seem an unlikely place to measure climate change, but it is one of the fastest-warming states in the nation. Its average temperature has climbed by close to 2 degrees Celsius since 1895 — double the average for the Lower 48 states.
Over the past two decades, the 2 degrees Celsius number has emerged as a critical threshold for global warming. In the 2015 Paris accord, international leaders agreed that the world should act urgently to keep the Earth’s average temperature increases “well below” 2 degrees Celsius by the year 2100 to avoid a host of catastrophic changes.
The potential consequences are daunting. The United Nations Intergovernmental Panel on Climate Change warns that if Earth heats up by an average of 2 degrees Celsius, virtually all the world’s coral reefs will die; retreating ice sheets in Greenland and Antarctica could unleash massive sea level rise; and summertime Arctic sea ice, a shield against further warming, would begin to disappear.
A Washington Post analysis of more than a century of National Oceanic and Atmospheric Administration temperature data across the Lower 48 states and 3,107 counties has found that major areas are nearing or have already crossed the 2-degree Celsius mark.
— Today, more than 1 in 10 Americans — 34 million people — are living in rapidly heating regions, including New York City and Los Angeles. Seventy-one counties have already hit the 2-degree Celsius mark.
— Alaska is the fastest-warming state in the country, but Rhode Island is the first state in the Lower 48 whose average temperature rise has eclipsed 2 degrees Celsius. Other parts of the Northeast — New Jersey, Connecticut, Maine and Massachusetts — trail close behind.
— While many people associate global warming with summer’s melting glaciers, forest fires and disastrous flooding, it is higher winter temperatures that have made New Jersey and nearby Rhode Island the fastest warming of the Lower 48 states.
The average New Jersey temperature from December through February now exceeds 0 degrees Celsius, the temperature at which water freezes. That threshold, reached over the past three decades, has meant lakes don’t freeze as often, snow melts more quickly, and insects and pests don’t die as they once did in the harsher cold.
The freezing point “is the most critical threshold among all temperatures,” said David A. Robinson, New Jersey state climatologist and professor at Rutgers University’s department of geography.
The uneven rise in temperatures across the United States matches what is happening around the world. Rhode Island is the first state in the Lower 48 whose average temperature rise has eclipsed 2 degrees Celsius.
In the past century, the Earth has warmed 1 degree Celsius. But that’s just an average. Some parts of the globe — including the mountains of Romania and the steppes of Mongolia — have registered increases twice as large. It has taken decades or in some cases a century. But for huge swaths of the planet, climate change is a present-tense reality, not one looming ominously in the distant future.
To find the world’s 2C hot spots, its fastest-warming places, The Post analyzed temperature databases, including those kept by NASA and NOAA; peer-reviewed scientific studies; and reports by local climatologists. The global data sets draw upon thousands of land-based weather stations and other measurements, such as ocean buoys armed with sensors and ship logs dating as far back as 1850.
In any one geographic location, 2 degrees Celsius may not represent global cataclysmic change, but it can threaten ecosystems, change landscapes and upend livelihoods and cultures.
In Lake Hopatcong, thinning ice let loose waves of aquatic weeds that ordinarily die in the cold. This year, a new blow: Following one of the warmest springs of the past century, harmful bacteria known as blue-green algae bloomed in the lake just as the tourist season was taking off in June. New Jersey’s largest lake was shut down after the state’s environmental agency warned against swimming or fishing “for weeks, if not longer.”
The nation’s hot spots will get worse, absent a global plan to slash emissions of the greenhouse gases fueling climate change. By the time the impacts are fully recognized, the change may be irreversible.
Daniel Pauly, an influential marine scientist at the University of British Columbia, says the 2-degree Celsius hot spots are early warning sirens of a climate shift. “Basically,” he said, “these hot spots are chunks of the future in the present.”
America’s hot spots
Nationwide, trends are clear. Starting in the late 1800s, U.S. temperatures began to rise and continued slowly up through the 1930s. The nation then cooled slightly for several decades. But starting around 1970, temperatures rose steeply.
At the county level, the data reveals isolated 2-degree Celsius clusters: high-altitude deserts in Oregon; stretches of the western Rocky Mountains that feed the Colorado River; a clutch of counties along the northeastern shore of Lake Michigan — home to the famed Sleeping Bear Dunes National Lakeshore near Traverse City.
Along the Canadian border, a string of counties from eastern Montana to Minnesota are quickly heating up. The topography of warming varies. It is intense at some high elevations, such as in Utah and Colorado, and along some highly populated coasts: Temperatures have risen by 2C in Los Angeles and three neighboring counties. New York City is also warming rapidly, and so are the very different areas around it, such as the beach resorts in the Hamptons and leafy Westchester County.
The smaller the area, the more difficult it is to pinpoint the cause of warming. Urban heat effects, changing air pollution levels, ocean currents, events like the Dust Bowl, and natural climate wobbles such as El Niño could all be playing some role, experts say.
The one U.S. region that has not warmed since 1895: the South, where data in some cases even shows a modest cooling. The only part of the United States that has not warmed significantly since the late 1800s is the South, especially Mississippi and Alabama, where data in some cases shows modest cooling. Scientists have attributed this “warming hole” to atmospheric cycles driven by the Pacific and Atlantic oceans, along with particles of soot from smokestacks and tailpipes, which have damaging health effects but can block some of the sun’s intensity. Those types of pollutants were curtailed by environmental policies, while carbon dioxide remained unregulated for decades. Since the 1960s, however, the region’s temperatures have been increasing along with the rest of the country’s.
The Northeast is warming especially fast.
Anthony Broccoli, a climate scientist at Rutgers, defines an unusually warm or cold month as ranking among the five most extreme in the record going back to the late 1800s. In the case of New Jersey, he says, “since 2000, we’ve had 39 months that were unusually warm and zero that were unusually cold.”
Scientists do not completely understand the Northeast hot spot. But fading winters and very warm water offshore are the most likely culprits, experts say. That’s because climate change is a cycle that feeds on itself.
Warmer winters mean less ice and snow cover. Normally, ice and snow reflect solar radiation back into space, keeping the planet relatively cool. But as the ice and snow retreat, the ground absorbs the solar radiation and warms.
NOAA data shows that in every Northeast state except Pennsylvania, the temperatures of the winter months of December through February have risen by 2 degrees Celsius since 1895-1896. And U.S. Geological Survey data shows that ice breaks up in New England lakes nine to 16 days earlier than in the 19th century.
This doesn’t mean the states can’t have extreme winters anymore. Polar vortex events, in which frigid Arctic air descends into the heart of the country, can still bring biting cold. But the overall trend remains the same and is set to continue. One recent study found that by the time the entire globe crosses 2 degrees Celsius, the Northeast can expect to have risen by about 3 degrees Celsius, with winter temperatures higher still.
In Rhode Island, Narragansett Bay has warmed as much as 1.6 degrees Celsius in the past 50 years, and for want of cooler water, the state’s lobster catch has plummeted 75 percent in the past two decades. Along the shoreline, the hotter and higher sea is shuffling the lineup of oceanfront homes.