The climate in New York has become subtropical: 5 indisputable facts

Winters in New York have become warmer, and summers are hotter, with heavy midday showers. Spring this year came a week earlier than usual. The newspaper writes about how the climate in the metropolis has changed in recent decades The New York Times.

The climate of New York City is temperate continental, with significant subtropical influences. However, in recent years the situation has changed somewhat, and the climate of the metropolis has become rather subtropical.

This is confirmed by an unusual story that took place in the early 2000s in the Brooklyn Botanic Gardens. When Chief Forester Chris Roddick made his rounds in May, he noticed that the fig trees had forgotten to cover for the winter. It is an annual tradition that immigrants from Italy brought with them when they arrived here about 100 years ago. The forester expected the fig trees to be damaged, or perhaps even disappear. But they were fine. In fact, they looked great. Figs produced a phenomenal harvest that year. “We used to just try to keep the plants alive,” Roddick said. "All of a sudden, it became clear that we can grow figs."

And this extraordinary phenomenon was only the beginning - it was followed by other evidence that the climate in New York is changing.

Today, new plant species are emerging in New York, and those more associated with New England are slowly disappearing. This is due to rising temperatures, which, according to the National Climate Assessmen, are largely the result of human activities, including emissions from fossil fuels.

After many years during which New York City was dominated by a humid continental climate, the city suddenly found itself in a humid subtropical climate zone. According to the classification, the temperature in summer here should be on average above 22 degrees Celsius - as it was in New York since 1927, and in winter - above -2,7 degrees Celsius. In the past five years, the city has met these requirements, despite the periodic cold snap. Meanwhile, the winters are only getting warmer.

For example, from January to March of this year, the average temperature in Central Park was 5,8 degrees Celsius, which is the second warmest in the history of the city. This was reported by Art DeGaetano, director of the National Oceanic and Atmospheric Administration's Northeast Regional Climate Center. The record was set in 2012, when the temperature reached 6,1 degrees Celsius. Spring, meanwhile, arrived two weeks earlier this year. Magnolia and cherry trees bloom in early March, although this usually occurs in April.

This summer, New Yorkers have experienced such weather events as heavy rains and real hurricanes. One of them happened not so long ago, at the end of June - a severe thunderstorm struck New Yorkleaving behind flooded streets and fallen trees. Moreover, this summer is recorded as one of the hottest on record.

Another confirmation of this is the sultry tropical nights. Today, there are about 15 such nights every summer when temperatures hover above 23,8 degrees Celsius. 60 years ago, there were rarely 10 such nights, DeGayetano said.

Due to climate change, the US Department of Agriculture adjusted the hardiness zone for plants in 2012. Tropical plants like yucca and some types of palm trees can now survive outdoors in all seasons except winter. New Yorkers can find them in sheltered, sunny areas around the city, such as south-facing locations next to buildings. The growing season is also longer, which means plants, branches and leaves have time to grow larger before the cold sets in.

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However, some gardeners are hesitant to adopt the subtropical classification of their city. Extreme cold temperatures are damaging plants, according to Todd Forrest, vice president of Horticulture and Living Collections at the New York Botanical Garden. “For now, I wouldn't try to grow the palm trees that grow in the tropical southeastern United States outside of New York,” Forrest said. "Three days of the polar vortex, and the plants will die." He believes the subtropical category is still more applicable to states such as Georgia, South Carolina, and Florida.

In terms of horticulture, the city's growing conditions now mimic those of Maryland, coastal Virginia and Washington as much as possible, Roddick and others said.

However, there are many clues that the climate in New York City has become subtropical. Here are a few of them.

1. Spring comes early

In the early days of the quarantine imposed in connection with the coronavirus pandemic, spring had already come into its own - the scent of pink and white flowers was in the air.

Gerald Giordano, senior horticultural consultant for the Westchester County Cooperative Extension, said he has noticed many changes in recent years. For example, his girlfriend, a resident of Tuckaho, New York, grows gladioli, which bloom just after winter ends. And the ivy that winds around some buildings in the city now blooms and even bears fruit.

Giordano recalls the moment when he first noticed the change in climate. “In the spring of 2011, everything happened as it had never happened before,” he said. - In the middle of March, cherry trees bloomed here. It was a real awakening moment for me. "

Such changes in climate can lead to the fact that the trees we are used to can change, according to Nina Bassuk, professor at the Urban Horticulture Institute at Cornell University. As the atmosphere warms up, several varieties of southern oak have already begun to move north. At the same time, local birches and maples are starting to experience problems due to the summer heat and drought, so they will gradually become less common.

In the coming years, native trees will be different from those that were here before Columbus, Bassuk added.

2. Southern plant species have successfully taken root and thrive

At the New York Botanical Gardens in the Bronx, what started out as an experiment - planting exotic species deemed too sensitive to survive outdoors during the New York winter - has become a successful and ongoing project.

Japanese apricots and camellias, which usually thrive in the south (camellia is the flower of Alabama, and the Japanese apricot was popularized at the North Carolina State University Arboretum), bloomed successfully last spring. Forrest noted that if 25 years ago he was asked whether such plants could survive without protection and appropriate care, let alone prosper, he would have answered in the negative.

Mr. Roddick of the Brooklyn Botanic Gardens said he was faced with further confirmation of climate change. This happened a few years after the fig tree story. According to him, the gardener was unable to cut the crepe myrtle tree, which used to freeze in winter. “We were shocked,” he said. He added that in the past 22 years, only one ice storm has damaged trees.

Myrtle trees (Crepe myrtles), commonly found in East Asia, India and parts of the Central and South Pacific, are also very common in the American South. Until recently, only small shrubs of this plant were found in New York. Gardeners cut them to their very roots for the winter.

Now in the Brooklyn Botanical Gardens, several varieties are grown all year round, and some of them grow up to 6-meter trees. They can be found throughout the city and the northern suburbs.

In the botanical garden, the endangered Chilean araucaria (Monkey puzzle tree) is also grown outdoors in pots all year round, while previously this plant only survived in the winter garden. "It's pretty amazing," Roddick said.

3. Weeds grow uncontrollably

Central Park and Botanical Gardens staff are currently focusing on uprooting weeds that are commonly found in warmer climates. “If we didn't pull it out all the time, it would easily cover the entire garden,” Forrest said.

And although nature was able to take a break from visitors during quarantine, when the botanical garden was closed to visitors, this allowed the weeds to show all their power. "Things that used to be minor problems have become big problems," Roddick said. “Poison ivy was everywhere. Invasive weeds of all kinds have taken root. "

4. A growing number of plant-eating pests

Beetles that used to die in winter now survive and can reproduce.

The biggest concern for people who grow plants is the spotted lantern fly, which lives in parts of China, India, Vietnam and East Asia. It enters America through ports, arriving from shipping boxes from around the world. Strong frosts allow to restrain the uncontrolled spread of this type of insects.

This type of insect feeds mainly on grapes and fruits. In recent years, these pests have been found in Pennsylvania and there is some concern that they will end up in New York. “We think it's a matter of time,” Roddick said.

5. The rains became stronger and the storms became more frequent

Every year, the city receives about the same amount of rainfall as in the past few decades, but instead of moderate rainfall, the rain comes in the form of floods. Moreover, more time passes between rains, which makes drought more likely.

When heavy rain suddenly hits a city, it usually stops just as quickly. The soil doesn't have time to absorb all the moisture, said Mark Fisher, a former vice president of horticulture at Brooklyn Botanic Gardens. Erosion is another problem that has come with climate change.

To retain moisture, the garden has an elaborate rainwater catchment system. Computer software dictates that the water level in ponds drops when rain is forecast, so ponds do not overflow during rain storms. Rainwater is filtered and reused for irrigation.

Going forward, more gardeners and homeowners will need these systems, said Rowan Blaik, assistant vice president of Living Collection at the garden. “This is a very gradual but very consistent change that we are seeing,” he said.

Meanwhile, preparing for storms has become another part of the gardener's work, Roddick said. “We have learned our lesson, let's put it this way,” he stressed.

In 2010, the hottest year that a tornado struck Brooklyn, the garden was taken by surprise. To cope with the consequences, garden managers had to stock up on chainsaws and train staff to use them. Then Easter came, and New York was hit by a hurricane, tropical storm and several more tornadoes. “Storm events, large and small, were so rare 20 years ago that no one had to prepare for them,” Roddick said. "And today we expect them."