People talk about the weather all the time. But that doesn’t mean people are good at remembering it years later. This summer has been hot. Is it hotter than last summer? The past 5 summers? The summer of 1999? You probably don’t know. We humans have short-term weather memory.
So you may not have noticed that all four seasons have changed. But scientists sure have noticed. They have been keeping careful track of our seasons. Test your skills of observation and memory against the PhDs and NASA satellites that are watching the earth.
Here are 4 yes or no questions, one for each season. Is your memory good enough to get all 4 correct?
1. Has summer always been this hot?
The summer heat really is getting hotter. Scientists measured that summer temperatures have risen since the 1970s, when Richard Nixon was still president. Unfortunately this extra heat can be dangerous, worsening droughts and heat waves.(1)
These sweltering summers are no fluke. Climate change makes record-breaking summer heat more likely each year. 2015 was the hottest summer ever recorded.(2) Someday you may look back and think of it as mild.
2. Have the fall leaves been changing colors later?
Fall leaves now fall off trees 10 days later into November. Compared to the 1980s, autumn in America arrive a week and a half later.(3) The vibrant reds, oranges, and yellows are appearing later as well. It’s not that fall has gotten shorter, it’s just moved backwards, starting later and ending later.(4)
Why is this happening? It’s getting warmer.
The Northeast has gotten 2°F warmer since the 1990s, and warmer days means later fall foliage. Trees wait for it to get cool before they begin changing their colors and dropping their leaves.(5) Observations show that the end of the growing season, marked by the first extreme frost, is occurring later each decade.
3. Is winter getting colder?
Source: NOAA & NCSU
You have warmer winters than your grandparents did, even though this past one was particularly cold. Back in their day, the thermometer went below freezing up to 19 more days each year. People may not have noticed, but birds definitely have.
Migrating birds like to live in the same temperatures they always have, so they’ve been flying farther north, chasing cooler weather. There’s a dark side to this: some birds might not be able to find suitable homes up north. That’s one reason why the Audubon Society warns that half of North American birds are at risk of extinction from a hotter climate.(6) They might run out of homes to fly to.
4. Is spring blooming sooner?
St. Patrick’s Day is the new unofficial first day of spring. In most of the country, trees are growing their first leaves 3 days earlier than they did in the 1960s and 1970s, moving from March 20th to March 17th, St. Pattie’s day.(7) This is not unwelcome news – spring is beautiful – even though it’s evidence of something bad: climate change.
A side effect of this new spring is worse allergies. If you’ve been sneezing more than you once did, it might be because there’s more pollen. Climate change has led to longer and more intense pollen seasons, and unfortunately this will create even more pollen in the future. Stock up on tissues.
Source: Ziska et al. 2000/Climate Central
Can you see the pattern?
Summers and winters are hotter, fall is coming later, spring is coming sooner: these are symptoms of America getting warmer all year round.
Our climate is getting hotter. These changes can be noticed from America’s backyards. Scientists say that if we don’t do anything about climate change, we should expect to see autumn start even later and summers get even hotter.
Exactly how much hotter? Well that depends on what America does next. The faster we develop solutions like clean energy and lead the world to act, the less our climate will change.
Two Possible Worlds for a Child Born in 2015
This is a unique time to be alive. The world is changing before our eyes. You can help preserve the seasons you’re used to, and a climate that’s better for America, by supporting a clean energy future.
- NIH, “Heat and Climate Change”
- CNN, “Earth’s Hottest Summer Ever”
- Climate Central, “Autumn is on the Move”
- Climate Central, “Autumn is Falling Back”
- Weather Channel, “Why Autumn Leaves May Be Dulled by Climate Change”
- National Geographic, “Climate Change May Put Half of North American Birds at Risk of Extinction”
- Climate Central, “Spring is Coming Earlier”
- Summer Temperatures – NOAA. Summer temperatures defined as the 5 year running average from June to September.
- Growing Season – Climate Central
- Decline in Snow Days – NOAA & North Carolina State University via NCA
- Spring is Coming Sooner – Climate Central
- Pollen Production – Climate Central
- U.S. Average Temperature – NOAA
- Two Possible Worlds – MIT. The temperature change is the difference between the target year and average temperatures from 1980-2000. The solid lines track the median projections in each case.