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  • These spiny spheres are plant pollen, as seen under a microscope.

  • They're the culprit behind most seasonal allergies.

  • Pollen can cause your immune system to kick into overdrive because your body sees the pollen as a harmful intruder.

  • As a result, the body produces histamines.

  • Normally, they promote healing by increasing blood flow and inflammation.

  • But they can lead to the nasty symptoms we associate with allergieslike sneezing, runny noses, and watery eyes.

  • Generally, people who suffer from allergies have it bad for several weeks during certain plants' growing seasons.

  • But because of climate change, the level of pollen in the air is getting much worse.

  • And that's bad newswhether you suffer from allergies or not.

  • In order to grow and produce pollen, plants need to generate energy through photosynthesis.

  • That requires water, sunlight, and a third necessary ingredient, carbon dioxide.

  • Carbon dioxide exists naturally in the atmosphere.

  • But as we burn fossil fuels like coal in power plants or gasoline in our cars, we're putting more and more CO2 into the air.

  • The more carbon dioxide there is in the air, the more plants grow and produce pollen.

  • Take a look at this graph.

  • These bars are the level of carbon dioxide in the atmosphere between 1996 and 2015.

  • And this line is the amount of pollen produced per ragweed plant, a common source of allergens.

  • As carbon dioxide increased, the ragweed produced more and more pollen.

  • And pollen is an important part of a plant's reproductive cycle.

  • So more pollen means more seeds, which means more plants producing more pollen the following season.

  • But CO2 is increasing the level of pollen in another way as well.

  • Carbon dioxide is a greenhouse gas.

  • And it's called that because it traps the sun's heat energy in the Earth's atmosphere and is helping warm the planetsort of like a greenhouse.

  • As the climate warms, there are more days above freezing, which means more time that plants are active and producing pollen.

  • This graph shows the number of days with above-freezing temperatures in the US over the past 120 years.

  • In the past 50 years, the US growing season has increased by over 10 days, on average.

  • And this isn't happening at the same rate everywhere.

  • This map shows the increase in pollen season for ragweed between 1995 and 2015.

  • While some places, like Texas, didn't see much change in their ragweed pollen season, most placesespecially those in the northern US and southern Canadasaw pollen season increase by almost a month.

  • And this isn't just happening in North America.

  • Overall, most places around the world are seeing longer growing seasonsand, as a result, more days with pollen as well.

  • Pollen levels and allergies are only going to get worse from here if carbon emissions continue the way they are.

  • This is the current production level of grass pollen, another common allergen source.

  • By 2060, that level is expected to double.

  • And by 2085, that amount will have more than tripled.

  • While allergies can be annoying for the 1 in 5 Americans that suffers from them, they can usually be kept at bay with over-the-counter drugs.

  • But in some, allergies can lead to severe reactions like anaphylaxis, where blood pressure drops and airways start swelling shut.

  • And pollen grains can wreak havoc on people's lungs, even if they don't suffer from seasonal allergies.

  • In the US, asthma attacks induced by pollen have led to more than 20,000 emergency room visits per year.

  • So if for no other reason than to protect your sinuses, it's important to reduce the amount of CO2 we're adding to the atmosphere.

  • It can help curb how much we're warming the planet and it can help slow the pollen apocalypse.

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These spiny spheres are plant pollen, as seen under a microscope.

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Why your allergies get worse every year

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    Vivian Chen posted on 2019/07/08
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