In this series of slides, we're going to look at indicators or evidence for climate change in New Jersey, looking primarily over the last century to upwards of about 125 years in the past. This will include a little mention again of sunny day flooding at the end of these slides, but first, let's start with annual temperature. This is a time series from the left 1895 to the right 2021 of temperatures, averaged across New Jersey for the year. And you can see there's ups and downs cooler years, warmer years. The horizontal line, there is the long term mean covering that period and the blue line on an angle there in the last 40 years or so, is the linear relationship, a linear trend of temperature during that time. And it just basically shows that the last 40 years temperatures have really taken off across New Jersey at a rate. If it was to go on for a century at that pace would be about 7° of warming. I also noticed that almost all of the warmest years on record have been in the last several decades. In fact, the two warmest years have been within the last decade or so. And a cool year in the last couple of decades is as warm as a warm year was back in the 20th century. So we've undergone a lot of warming in New Jersey, particularly in the last 40 years, but it's not all about warming. This isn't just global warming, this is global climate change, and more specifically New Jersey climate change. And we need to look at a very important variable and that is precipitation, But the water falling from the skies as rain and at times snow. And we melt that snow down to get what's called the water equivalent of that snow. We added all together over the course of the year from multiple stations around the state and we come up with a statewide average precipitation for an individual year. Again, you can see the long term mean they're horizontally and a 40 year linear regression to the right that shows you that New Jersey is getting wetter in recent decades. But something that's even just as interesting is the fact that the year to year variations in precipitation are becoming more extreme. You look back in the first half or so of the 20th century and you don't have as much year to year variability as you do in recent decades, especially since the great drought of the mid 60s. You go, and you look at the variability, you can still have some dry years, but we've had almost all of the very wettest years in just the last 50 years across the state, including 2011 and 2018. Which by far the two wettest years on record in New Jersey, but it's not all about wetness. We do have some dry years as well. So we've gotta be prepared to handle that wide range of precipitation from drier years, to years that are wet often involving flooding as well. And particularly as we look at those wetter years, it's how is that rain falling? And this next slide shows you how we're seeing more frequent large rainfall events. So the take home here is that in recent decades it's been more a case of when it rains it horse. So go with that adage, if it helps you remember that we're seeing more of our rain fall in larger precipitation events, not seeing more days of the year with rain. But because the climate is getting warmer, we can hold more water vapor in the atmosphere, more water vapor can evaporate from the nearby ocean surfaces. And when a trigger comes along, it can squeeze more of that moisture out of the atmosphere. Now, if there's not a trigger comes along, it can be dry for a period of time and we can go up and down in terms of dry and very wet and dry and very wet. But the point is that there's physical laws here that show that with a warmer atmosphere, you have the potential of having more moisture in the atmosphere. And when an impetus comes along to squeeze that moisture out, we can have extreme heavy rainfall events. And that has manifested itself in more flooding over recent decades. This is just one snapshot from one river basin. And it's the millstone river basin, there's a gauge of Blackwells Mills a little bit upstream from Manville where these photographs were taken, and there's a century of record from that station. And what we see from that record is that six of the eight largest floods on the lower Millstone River in the last century have all occurred since 1999. That in 1999, you see a photograph that was Floyd. You look at the lower right photo, that's Irene, 2010 and 22007 were nor'easters. I didn't get my camera out there in 2014 for another nor'easter nor for Ida in September of 2021. But again, the take home is six of the eight largest floods in a century have all occurred in just the last couple of decades, when it rains, it pours. Now let's look at sea level again, this is a title gauge at Atlantic City, and what it shows going back over a century is an upward swing of sea level along coastal New Jersey. About 15 plus inches of sea level rise during that time. And there's several reasons why that the seas have risen and it actually includes the fact that the land is sinking a little because we're pulling water out of the ground in wells. And also there's some sinking of the land that's related to the ice sheet that sat to the north in New Jersey and helped the land bulge up to the south. And that bulge has been retreating over the last 20,000 years. But more importantly, the major factor here is that the oceans are getting warmer and what we call thermally expanding. And there's more water going into the oceans from melting ice sheets and glaciers. So there's multiple things going on here. But the overall trend is for upward rise in sea level along the New Jersey coast over the last century. With that sea level rise, even on sunny days with a new moon or a full moon and no storm nearby, we're seeing the water's encroach upon low lying streets and neighborhoods along the Jersey shore. And this shows you an example of tidal flooding and Manilow going in the top. But the bottom figure shows you over the last century the number of days down in Atlantic city with this type of nuisance flooding. And you can see it was a day or two a year for most of the 20th century. When you got to the 90s, you started seeing a handful of days a year, and now it's closer to 8 to 10, sometimes more days a year. So we're seeing quite an increase in the number of days with this sunny day or nuisance type of flooding. But as you saw in the first vignette, I recorded for you, and you'll see again subsequently that pals the number of days they're pale in comparison to what we expect in the coming years. So with that we finished up with this second little vignette stay tuned for the next one, where we'll be talking more about how we monitor the climate system across New Jersey.
