The sun was shining. Flowers were beginning to bloom. And families curled up inside their homes for warmth during a brutal winter began to emerge into the warm, mild air that signaled to them that it was the beginning of Spring.

The only problem was it, it wasn’t Spring at all – it was the end of December.

What was going on?

If you had told me on Thanksgiving, when my first child, Thomas Hunter was born, that come Christmas, our new family of three would enjoy a comfortable walk around the neighborhood in short sleeves, I would have said that you were crazy. But there we were, sweating as we pushed our newborn around in 70-degree weather.

Tom Moderating at the COP21

Just a few days after his birth, began arguably one of the most important global gatherings of our lifetimes.  Leaders from across the world arrived to the outskirts of Paris with the expressed goal of cobbling together an agreement on how to tackle human-caused climate change at what was known as COP21 (COP stands for Conference of Parties and it was the 21st one).

And I, as any good first time father would do, flew clear across the Atlantic Ocean to Paris for two weeks to emcee the US State Department’s public outreach portion of its COP involvement called the US Center. I’d like to point out that my wife is a saint, because that meant I would be away during the first two weeks of my son’s life, which was incredibly important to me, and to our new family.

For the first two weeks of December, I was helping introduce and lead events with US and global decision makers while my wife and my son’s now-grandparents were helping get our child accustomed to life outside the womb. While I was introducing cabinet members, my wife was being introduced to a newborn sleep schedule. Have I mentioned that my wife is a saint? But there was a very good reason why we, together, decided that I could leave so soon after Thomas Hunter’s birth.

What was being decided at that COP21 event was aimed at providing my son’s generation, and their future children a fighting chance at a stable climate in their lifetimes. Not a future whose climate is revved up to a metaphorical 11.

Meanwhile, during that conference time back at home, Mother Nature was making sure the start to Winter was record-breaking. As many of you may remember, December was ridiculously warm for the eastern half of the country.

A view of the temperature trends in he US in December 2015 Source:

A view of the temperature trends in he US in December 2015 Source:

In New York City, December averaged 50.8 degrees Fahrenheit, over 13 degrees above normal, obliterating the previous record of 44.1 degrees set in 2001. And for the first time since records began in Central Park, and LaGuardia, JFK and Newark airports, the daily low temperature did not reach 32 degrees once. That’s right. In December, the temperature never once got below freezing in New York City.

In Washington DC, where I live, December set records for warmth at all three major airports. Washington National Airport broke the previous December average temperature record by 5.6 degrees! Boston had its warmest December by over 4 degrees from the previous record. In fact, almost every state in the eastern half of the country set a record for warmest December at about 10.6 degrees above average. In conclusion, it was a weird warm month for many of us.

December’s US records took place during a year where global temperatures were steadfastly crushing all previous years on record, but even this is not exactly “climate change.” It’s not as simple as a month or a year of warm temperatures, it’s about the broader picture.

What you need to know is that climate is not a single weather event. The climate of the globe, a region, or the city you live in is all of the weather events that impact that particular area.

When we talk about climate change, we’re not just referring to seeing fundamentally different weather events (although we do/will see them), it’s that we see more of certain weather events. We will tend to see more warmer than average days and wetter than average days than in the past.

But picking any individual event and saying “Look here, climate change!” isn’t so much wrong but an attempt to say one piece of the climate puzzle shows you the whole picture. It doesn’t.

Tropical Storm per the El Nino Effect

Tropical Storm per the El Nino Phenomenon

In fact, the odd weather in December had its roots in normally occurring weather and climate phenomena.

Remember the polar vortex? It’s an area of low pressure (a wide area of swirling cold air) located on the Earth’s polar regions. Last winter, a weak northern polar vortex led to cold air spilling over the eastern US. This December the polar vortex has been strong which has kept that cold air hunkered down over the Arctic and warmer air over the US. Add in a strong El Niño (top 3 since 1950) phenomenon t in the Pacific, which usually leads to warmer than average winter temperatures across the northern tier of the US, and these events can line up without help from climate change to cause above-normal temperatures.

We cannot blame the December temperatures on climate change.

But we also know that this event took place in a world already warmer thanks to climate change (and only will get more amped the less we as a species do anything about it). While not the cause of the warm temperatures, it exacerbated the situation.

To make this concept clearer, indulge me in a weird analogy:

Imagine you live in a house with a couple of pet rats who you refuse to keep locked in their cages. They escape into your house but you go about living your life.

Occasionally, you hear things fall. Cereal from a shelf. Books from a table. Nothing out of the ordinary but you are always left wondering …“was it the rats?”

Of course, you continue to buy more pet rats that you refuse to lock up, who escape and begin making more rats with the previous escapees. Eventually after a long period of time, there are rats everywhere. Books flying off shelves. Food opened, eaten and spread across the floor. You are a lot more confident in saying “Yup, that’s obviously the rats.”

Translation: for most weather events, we haven’t reached “yup, that’s the rats!” stage, but the rats still had some influence.


The Author and His Family

Asking whether any individual event happening today was “caused” by climate change seems like a straightforward question but isn’t. Any event has a multitude of causes. Instead, when my son grows up and hopefully stops farting in my general direction as much, and asks about whether an event was caused by climate change, I will encourage him to think of it this way: what we are seeing is like getting into a time machine and flying off into your child’s future. A future where these absurd events are not odd or even newsworthy but commonplace. And that doesn’t even include some surprises to our climate system that we just don’t know about yet.

The scale of climate change is large. The importance in solving it is immense. Which is why, as an atmospheric scientist and father, I know that I am not going to look back at this time and say that I didn’t do all that I could to raise an alarm based on solid science. Because what the science says is scary enough. There is no need to hype it.

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Categories: Science 101 + Mythbusting