Home / Tag Archives: climate change

Tag Archives: climate change

What do we know about nighttime minimum temperatures?

The recent article on Climate.gov Extreme overnight heat in California and the Great Basin in July 2018 by Rebecca Lindsey (8/8/18) provides an overview in context.

As the NCEI’s Deke Arndt has blogged about before, nighttime low temperatures are increasing faster than daytime high temperatures across most of the contiguous United States. For much of the West and Southwest, July’s record-breaking nighttime heat is a new highpoint in a long-term trend—one that has rapidly accelerated in recent decades. In California, average overnight low temperature in July rose by 0.3°F per decade over the historical record (1895-2018), but since 2000, the pace of warming has accelerated to 1.3°F per decade.

Here is an example of why this matters:

According to Tim Brown, director of NOAA’s Western Region Climate Center (WRCC), it’s a pattern that has serious consequences for wildfires and those who combat them. When temperatures cool off overnight, it’s not just a physical relief for firefighters who may be working in conditions that push the limits of human endurance; fire behavior itself relaxes as temperatures drop, winds grow calmer, and relative humidity rises.

The graph here for California July minimum temperature is from the article. A stats course can have students create a similar graph for their hometown. Go to  NOAA’s Local Climatological Data Map. Click on the wrench under Layers. Use the rectangle tool to select your local weather station. Check off the station and Add to Cart. Follow the direction from their being sure to select csv file. You will get an email link for the data within a day.  Note: You are limited in the size of the data to ten year periods. You will need to do this more than once to get the full data set available for your station.

The map here  shows statewide minimum temperature ranks for July 2018.  It is from NOAA’s National Temperature and Precipitation Maps page.  Under products select Statewide Minimum Temperature Ranks and choose the desired time period.  A map similar to the one in the article can be generated by selecting CONUS Gridded Minimum Temperature Ranks.

What are the recent Mauna Loa CO2 measurements?

NOAA: https://tinyurl.com/y9opmjxg

The  NOAA article Another Climate Milestone on Mauna Loa (6/7/18) provides an overview of CO2 measurement at the Mauna Loa site.  In particular,

Carbon dioxide levels measured at NOAA’s Mauna Loa Atmospheric Baseline Observatory averaged more than 410 parts per million in April and May, the highest monthly averages ever recorded, scientists from NOAA and Scripps Institution of Oceanography at the University of California San Diego announced today.

There is also this point:

From 2016 to 2017, the global COaverage increased by 2.3 ppm – the sixth consecutive year-over-year increase greater than 2 ppm. Prior to 2012, back-to-back increases of 2 ppm or greater had occurred only twice.

Why Mauna Loa?

The Mauna Loa observatory is ideally located for monitoring CO2 and other greenhouse gases in the atmosphere. Situated at more than 11,000 feet above sea level in the middle of the Pacific Ocean, the site gives researchers the opportunity to sample air that has been well-mixed during its passage across the Pacific and, thanks to its altitude, is minimally influenced by local vegetation or local pollution sources.

The article links directly to CO2 data sets and other resources.  The Calculus Projects page here has a Mauna Loa CO2 project and the Misc Materials page has the CO2 movie.

How hot has it been this week?

Simulation of maximum temperatures on July 3 from American (GFS) weather model at two meters above the ground. (University of Maine Climate Reanalyzer)

The Washington Post article, Red-hot planet: All-time heat records have been set all over the world during the past week by Jason Samenow (7/5/18), provides a nice overview of the record setting heat during this past week (map posted here copied from the article).  In North America:

Montreal recorded its highest temperature in recorded history, dating back 147 years, of 97.9 degrees (36.6 Celsius) on July 2. The city also posted its most extreme midnight combination of heat and humidity.

Ottawa posted its most extreme combination of heat and humidity on July 1.

In Europe:

Excessive heat torched the British Isles late last week. The stifling heat caused roads and roofs to buckle, the Weather Channel reported, and resulted in multiple all-time record highs:

In the Middle East:

As we reportedQuriyat, Oman, posted the world’s hottest low temperature ever recorded on June 28: 109 degrees (42.6 Celsius).

Maps of temperature anomalies can be created for various time periods from NASA’s GISS Surface Temperature Analysis page. June isn’t available yet but it will be before long.  Monthly Global Climate reports are available from NOAA. June isn’t available yet, but here are two highlight from May:

The contiguous U.S. May 2018 temperature was 2.89°C (5.2°F) above the 20th century average and the highest May temperature since national records began in 1895. This value exceeds the previous record set in 1934 by +0.4°C (+0.7°F).

Europe had its warmest May since continental records began in 1910 at +2.76°C (4.97°F), surpassing the previous record set in 2003 by +0.92°C (+1.66°F). May 2018 marks the first time in May that the continental temperature departure from average is 2.0°C (3.6°F) or higher.

How much are 30 year temperature averages increasing?

Changes in 30 year temperature averages depend on where you live, but Climate Central’s New Normal: Temperatures Are Trending Up Across U.S.  (3/16/18) has graphs for major cities across the U.S. The one here is for the U.S.

Normal temperatures, generally defined to be the 30-year average at a location, are trending up across most of the U.S. Since 1980, the average continental U.S. temperature has risen 1.4°F.

This is a change in the 30 year average so that the value for 2017 is the average from 1988-2017. In other words, the climate is changing.  A nice primer on the difference between weather and climate can be found at the NSIDC Climate vs Weather page:

Weather is the day-to-day state of the atmosphere, and its short-term variation in minutes to weeks. People generally think of weather as the combination of temperature, humidity, precipitation, cloudiness, visibility, and wind. We talk about changes in weather in terms of the near future: “How hot is it right now?” “What will it be like today?” and “Will we get a snowstorm this week?”

Climate is the weather of a place averaged over a period of time, often 30 years. Climate information includes the statistical weather information that tells us about the normal weather, as well as the range of weather extremes for a location.

The Climate Central post has a drop down menu and you can choose the graph for the city closest to you to see how much your climate has changed.  They don’t post the data that was used to create the graphs, but you can find the data for a location near you. Try starting with this NOAA map (look for a future post on using this portal for local data). This could be a great stats project for students.

 

How fast is Antarctica melting (and a quick calculus project)?

A recent NYT article, Antarctica Is Melting Three Times as Fast as a Decade Ago by Kendra Pierre-Louis (6/13/2018), states clearly that Antarctica is melting, well, three times faster than a decade ago, which is a rate of change statement. Rapid melting should cause some concern since:

Between 60 and 90 percent of the world’s fresh water is frozen in the ice sheets of Antarctica, a continent roughly the size of the United States and Mexico combined. If all that ice melted, it would be enough to raise the world’s sea levels by roughly 200 feet.

Any calculus student can roughly check the melting statement.  Antarctica ice data is available at NASA’s Vital Signs of the Planet Ice Sheets page. There you can download change in Antarctica ice sheet data since 2002. (Note: The NYT article has a graph going back to 1992, but ends in 2017 as does the NASA data.) A quick scatter plot and a regression line shows that the change is not linear and the data set is concave down. (The graph here is the NASA data and produces in R – the Calculus Projects page now has some R scripts for those interested.)  Now, a quadratic fit to the data followed by a derivative yields that in 2007 the Antarctica was losing 95 gigatonnes of ice per year and in 2017 it was 195.6 gigatonnes per year. Even with this quick simple method melting has more than doubled from 2007 to 2017. The NYT article states:

While that won’t happen overnight, Antarctica is indeed melting, and a study published Wednesday in the journal Nature shows that the melting is speeding up.

This is an excellent sentence to analyze from a calculus perspective. Given that the current trend in the data is not linear and at least about quadratic, then melting is going to increase each year.  On the other hand, maybe they are trying to suggest that melting is increasing more than expected under past trends, for example the fit to the data is more cubic than quadratic. In other words, is the derivative of ice loss linear or something else? If everyone knew calculus the changes in the rate of ice loss could be stated precisely.

How much are the oceans warming?

A year ago Climate Central posted the article Oceans Are Heating Up with a graph of sea surface temperature anomalies while providing context on issues of ocean warming:

 93 percent of the excess heat absorbed by the climate system goes into our oceans, creating major consequences. While more extreme storms and rising sea levels are some of the impacts of warmer oceans, rising CO2 levels and the resulting warmer oceans are impacting ocean health itself. The most well­ known effects are coral bleaching and ocean acidification, but an emerging issue is the decreasing oxygen levels in the warming waters.

The graph here is from NOAA’s Global Ocean Heat and Salt Content page. There you will find numerous updated graphs related to ocean heat content.  For related data go to NOAA’s Basin time series of heat content page to find about 50 time series on ocean heat.

For context on units, a person at rest typically generates about 60 joules of heat per minute while the graph here has y-axis units of 10^22 Joules.

What is the state of the Rio Grande?

The NYT article, In a Warming West – the Rio Grande Is Drying Up by Henry Fountain (5/24/2018) answers the question.

Even in a good year, much of the Rio Grande is diverted for irrigation. But it’s only May, and the river is already turning to sand.

“The effect of long-term warming is to make it harder to count on snowmelt runoff in wet times,” said David S. Gutzler, a climate scientist at the University of New Mexico. “And it makes the dry times much harder than they used to be.”

With spring runoff about one-sixth of average and more than 90 percent of New Mexico in severe to exceptional drought, conditions here are extreme. Even in wetter years long stretches of the riverbed eventually dry as water is diverted to farmers, but this year the drying began a couple of months earlier than usual. Some people are concerned that it may dry as far as Albuquerque, 75 miles north.

What the article is missing is data. For example, we have here a graph of daily discharge in cubic feet per second at the Albuquerque station (directions below on how to obtain this graph and associated data.).  Note, that the graph is on a log scale and so is there is downward trend in this data?  Since 1991, the Rio Grande hasn’t stopped flowing in Albuquerque, although is came close around 2014.  Other stations farther south have periods of zero discharge. Use the directions below to explore water flow of the Rio Grande at several locations.  The data is naturally collected as a rate and so it is interesting for calculus classes as well as statistics classes.

To obtain water flow data at any USGS station around the country start at the National Water Information System: Mapper (Note: Different sites around the country will have different dates and type of data available.) Click on any of the sites to get a window with a link to access the data.  The graph here comes from selecting the USGS 08330000 RIO GRANDE AT ALBUQUERQUE, NM station. On that page under Available data for this site  select Time series: Current/Historical observations. For this specific graph we selected a time frame for the whole data set and selected Graph.  You can also select tab-separated file, as well as a few other options.  Further historical data for the Rio Grande can be found at the Rio Grande Historical Mean Daily Discharge Data page.

How old is Arctic sea ice?

From the NYT: In the Arctic, the Old Ice Is Disappearing

The NYT article In the Arctic, the Old Ice Is Disappearing by Jeremy White and kendra Pierre-Louis (5/14/2018) notes

In the Arctic Ocean, some ice stays frozen year-round, lasting for many years before melting. But this winter, the region hit a record low for ice older than five years.

In fact, in March of 1984 5+ year old ice made up about 70% of all ice and now it makes up only a few percent. There is also less ice overall.

If you really want to explore changes in the age of  Arctic ice go to the NSIDC Satellite Observations of Arctic Change interactive graph.  You can choose a year from 1985 through 2916, see a map of the ice, a bar chart of ice by month by age, and have the graph animate through the months of the year. The differences over the years is extreme. You can get related data from the EASE-Grid Sea Ice Age, Version 3 page, although you will have to register.

How many Billion dollar weather/climate disasters occur in the U.S. each year?

NOAA has your answer on their Billion-Dollar Weather and Climate Disasters: Time Series page. The page includes an interactive version of the graph here that allows you to select disaster types and adjust for CPI.  The data is available to download.

Determining the cost of disasters is not simple and they note:

In May 2012, NOAA’s National Centers for Environmental Information — then known as National Climatic Data Center (NCDC) — hosted a workshop including academic, federal, and private sector experts to discuss best practices in evaluating disaster costs.

A research article “U.S. Billion-dollar Weather and Climate Disasters: Data Sources, Trends, Accuracy and Biases” (Smith and Katz, 2013) regarding the loss data we use, our methods and any potential bias was published in 2013. This research article found the net effect of all biases appears to be an underestimation of average loss. In particular, it is shown that the factor approach can result in an underestimation of average loss of roughly 10–15%. This bias was corrected during a reanalysis of the loss data to reflect new loss totals.

A climate.gov post by Deke Arndt (4/13/18) , The all things being equal edition, discusses the connection between weather and climate:

Relative sea level in and around Boston has risen about half a foot in the last 50 years. So, all else being equal, the same storm 50 years ago would have six inches less water to push inland. That’s a big, big difference, and one that has developed on the climate scale.

That’s how climate comes in, even in these weather events. Many times, in the discussion of weather and climate, we mistakenly consider these two words, and the concepts they define, to be mutually exclusive frames.

How much has growing season/allergy season increased in your town?

Climate Central has your answer with their post, Here’s How Frost-Free Season Affects Allergy Season (4/4/18). You will find a drop down menu to produce graphs like this one for Grand Rapids, which has seen as average increase of about 25 frost free days. On the downside,

 A study sampling 10 locations from Texas to Saskatoon, Canada indicated that pollen seasons lengthened between two to four weeks from 1995 to 2009, with the largest increases in the northernmost areas.

In addition, increasing atmospheric carbon dioxide enhances photosynthesis in plants, meaning that they produce more pollen.

They don’t provide the data, unfortunately, but they do provide a clear methodology so that you can create the data set for your city. You can get weather data from NOAA Climate Data Online. There is great potential here for student projects in statistics courses.