How does climate impact Arctic communities?

The graph here is from the paper Co-production of knowledge reveals loss of Indigenous hunting opportunities in the face of accelerating Arctic climate change in Environmental Research by Donna D W Houser, et. el. (8/24/2021). From the discussion:

Overall, our analyses indicate that the ugruk harvesting season for Qikiqtaġruŋmiut hunters is being compressed by the shorter spring ice breakup period. Indeed, if we summarize across our time-series from 2003 to 2019, Kotzebue Sound now clears of sea ice ∼22 d earlier (figure S3) and is the primary factor contributing to a shrinking ugruk hunting season.

A new Indigenous-led study documents how ice loss is changing seal hunts by Yereth Rosen (9/6/2021) is non-technical summary of the paper and when an article has a rate in it we can use it in calculus:

From 2003 to 2019, the seal hunting season diminished by about a day a year, with most of that change happening at the end of the season, according to the study, published in the journal Environmental Research Letters.

How much CO2 have we emitted in the last 30 years?

The Institute for European Environmental Policy had this post that I missed in 2020 but it is still good: More than half of all CO2 emissions since 1751 emitted in the last 30 years (4/29/2020).

Slightly over half of all cumulative global CO2 emissions have taken place since 1990, the year of the first IPCC Assessment Report. The report re-confirmed anthropogenic climate change in a way that could not be ignored and led to the creation of the UNFCCC.

As a project you can do something similar comparing China and the U.S. using the U.S. and China CO2 Emissions projects under Calculus Projects.

Southwest drought, bad luck or more to come?

From the article NOAA-led drought task force concludes current Southwest drought is a preview of coming attractions by Rebecca Lindsey (9/23/2021):

The team found that the record-low precipitation that kicked off the event could have been a fluke—just the rare bad luck of natural variability. But the drought would not have reached its current punishing intensity without the extremely high temperatures brought by human-caused global warming.

The key points:

The cumulative precipitation for the 20-month period was the lowest on record, dating back to 1895. That left almost the entire western half of the contiguous United States in some level of drought at the end of August.


Meanwhile, the average temperatures over the same 20-month period were near-record high. High temperatures make the atmosphere thirsty for moisture, which it draws vigorously out of the region’s soil, rivers, lakes—even the snowpack. This atmospheric demand, called a vapor pressure deficit (“VPD” for short), reached record highs during the current drought.

No relief in site:

As for when the current event will break, the task force warns that it’s unlikely to be this winter. Thanks in part to the expectation that La Niña will settle into the tropical Pacific by later this fall, odds are that winter precipitation across the Southwest will be below average once again. That means the drought will likely persist well into 2022, and perhaps longer, depending on how unfavorable the coming wet season is.

There is a link to the full report for those interested.

Did COVID-19 impact births?

The U.S. Census Bureau article U.S. Births Declined During the Pandemic by Anne Morse (9/21/2021) has the data.

However, comparing one month during the pandemic to the same month before the pandemic shows a substantial drop that can’t be explained by seasonality.

There were 285,138 births in December 2020 — 23,664 (7.66%) fewer than in December 2019. On average, there were 763 fewer births each day in December 2020 than in December 2019.


Not all of the decrease in births should necessarily be attributed to the pandemic. The number of U.S. births has been declining every year since 2008 (except 2014).

Between 2000 and 2019, the number of daily births declined an average 0.39% a year. The pace of decline accelerated between 2010 and 2019, when the number of daily births dropped on average 0.96% a year.

But the decline was much steeper in in 2020: The average number of daily births was 4.06% lower than in 2019.

There is a table of data in the article and sources are cited for the data.

How do we explore invasive aquatic species in the Great Lakes basin?

The Great Lakes Aquatic Nonindigenous Species Information System (GLANSIS) is

designed to to be a “one-stop shop” for information about non-native species in the Great Lakes. GLANSIS hosts regional data about identification, ecology, distribution, environmental and socioeconomic impacts, management, and control of nonindigenous species throughout the Great Lakes basin, along with bibliographic material, risk assessments, and other resources.

If you click on Map Explorer you can make the map here which shows the distribution of Bythotrephes longimanus (Spiny Waterflea – orange) and Echinogammarus ischnus (scud – blue). One nice thing about the Map Explorer is you can easily download a csv file of the data which includes lat long  coordinates (use it in your favorite GIS software). There are also dates so the data can be used as a time series.  Using the GLANSIS Map Explorer by El Lower, Austin Bartos, and Rochelle Stuttevant (8/11/2021) provides an nice intro to the site.

How hot was August 2021?

From NOAA’s Global Climate Report – August 2021:

The August 2021 global surface temperature was 0.90°C (1.62°F) above the 20th century average of 15.6°C (60.1°F). This was the sixth warmest August on record. Nine of the 10 warmest Augusts have occurred since 2009. August of 1998 still ranks among the 10 warmest on record. August 2021 was also the 45th consecutive August and the 440th consecutive month with temperatures, at least nominally, above the 20th century average.

And for land only:

Averaged as a whole, the global land-only surface had a near-record high August temperature at 1.34°C (2.41°F) above average, which is only 0.04°C (0.07°F) less than the record-warm August set in 2016. This was mainly driven by the very warm land-only surface temperatures across the Northern Hemisphere, which had its warmest August on record at +1.44°C (+2.59°F). This value surpassed the previous record set in 2016 by 0.04°C (0.07°F).

More info and data available on the page.

What is the Groundswell report?

From the world bank:

This sequel to the Groundswell report includes projections and analysis of internal climate migration for three new regions: East Asia and the Pacific, North Africa, and Eastern Europe and Central Asia. Qualitative analyses of climate-related mobility in countries of the Mashreq and in Small Island Developing States (SIDS) are also provided. This new report builds on the scenario-based modeling approach of the previous Groundswell report from 2018, which covered Sub-Saharan Africa, South Asia, and Latin America. The two reports’ combined findings provide, for the first time, a global picture of the potential scale of internal climate migration across the six regions, allowing for a better understanding of how slow-onset climate change impacts, population dynamics, and development contexts shape mobility trends.

Key projection:

Over 216 million people could move within their countries by 2050 across six regions,

The report discusses their modeling (there is more than this) :

Both Groundswell reports use the same modeling approach, which allows for direct comparison of results and for aggregation to derive the global figure for internal climate migration. They take a scenario-based approach and implement a modified form of a gravity model to isolate the projected portion of future changes in spatial population distribution that can be attributed to slow-onset climate factors up to 2050. The Spotlight discusses the key innovations and scope of the modeling approach.

Quiz question for a class: Is the 216 million people a lot or a little?



What is the status of Lake Mead?

About two months ago I had the post How low is Lake Mead?  The graph in the post was the yearly minimum end of month elevation. In this post we have a closer look at the end of month elevation since 2011. The last month in the data is July 2021, which is a record low following the previous record low in June 2021. In the previous post I mentioned that this really should be given in some per capita format. I’ll add that presumably the decrease in the volume of water is not linear with the lake elevation. Data here.

How much will tidal flooding increase?

The graph below shows the number of days per year that sea level in Kings Point, NY is projected to exceed 60 cm above MHHW.

Sea level rise will increase the likelihood of tidal flooding. NASA has posted a tool, Flooding Days Projection Tool, to help understand how much tidal flooding may increase. There is a drop down menu for numerous locations in the U.S.  For example, the graph here is for Kings Point, NY.  Along with the value of the data there are calculus terms in the post:

These projections are based on unique, location-specific relationships between annual mean sea level, the top 1% of astronomical tides in each year, and annual counts of threshold exceedances.

An interesting and essential feature of these graphs is that the number of flooding days per year does not necessarily increase smoothly in time. In most cases, there are inflection points where the frequency of flooding days increases rapidly, which may be useful when establishing planning horizons. In many locations around the United States and its territories, there are sharp inflection points around the mid-2030s that are related to the interaction between accelerating sea level rise due to climate change and a long-term, 18.6-year cycle in the amplitude of astronomical tides.

And discussions of probabilistic modeling:

The purpose of this tool is to produce probablistic projections of flood frequency in the future that provide information about the full range of possibilities for a given year, including the potential for the occasional—yet inevitable—severe years. The projections leverage the predictability inherent in certain contributions (e.g., tidal amplitude and climate-change-induced sea level rise) and use statistical methods to account for everything else. The projections are probabilistic, because rather than producing a single, most-likely number of flooding days for a future year, these projections produce a range of plausible numbers with probabilities assigned to each possibility or range of possibilities.

All in all this is a great resources for math classrooms.