Geography week 1

GEO$SCI(100(

Global(Environmental(Change(

Welcome! GEOGRAPH 110

Global Warming – Understanding the Forecast, 2nd Edition by David Archer

http://forecast.uchicago.edu/lectures.html

PDF file: https://maths.ucd.ie/met/cess/FoundClim/arc her_global_warming.pdf

Suggested Course Text

There is a series of lecture videos, taught by Dr. David Archer of Chicago University, the author of this book that are available online. While his lectures are wonderful and inspiring, please know that the lectures are for an introductory physics class and may cover more detail than necessary for this course. For lecture videos, please go to (http://forecast.uchicago.edu/lectures.html).

Arctic Climate Change – Who Cares?

More story, go to http://nsidc.org/arcticseaicenews/ 2013/09/draft-arctic-sea-ice- reaches-lowest-extent-for-2013/

Let me begin this course by presenting an impact of climate change observed in the Arctic. This figure shows the Arctic sea ice extension in September 2012. The purple solid line was the arctic extension in 1979. The 2012 minimum, which correlates closely with the ice visible through clouds in this image, fell substantially below previous records. Why do we care? One of our goals is to learn why this is happening, especially in the Arctic – also, why do we need to care about this phenomenon.

Arctic Climate Change

Differences during the summer is increasing while sea ice

extension is decreasing in the recent past.

To view other years, please visit the interactive web site at https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

First, important things to keep in mind when we discuss Arctic conditions is that sea ice extension varies seasonally. It may be strange to think that sea ice will naturally melt in the Arctic, but the sea ice recedes seasonally, when the surface sea temperature exceeds freezing level [e.g., Average July temperatures range from about −10 to +10 °C (14 to 50 °F)].

This figure shows the month to month sea ice extension from 2010 to 2014. Sea ice grows to its maximum during the early spring and to its minimum in September (late summer). This cycle seems to show similar patterns for the past 6 years, except for the time of minimum in 2012. The minimum extension in 2012 was obviously significantly reduced compared to the past 6 years of observation.

We will cover more on this topic in future lecture slides. For now, to view other years, please visit the interactive web site at: https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

Climate Change in Continental Glacier Not only true for sea ice, but continental glaciers show a similar trend.

http://nsidc.org/cryosphere/sotc/glacier_balance.html

1928-2000 comparison: These photos of the South Cascade Glacier in the Washington Cascade Mountains show dramatic retreat between 1928 and 2000. Photos courtesy USGS.

https://e360.yale.edu/features/andes-meltdown-new-insights-into-rapidly-retreating-glaciers

Andes Meltdown: New Insights Into Rapidly Retreating Glaciers

http://www.climatecentral.org/gallery/graphics/arctic-paradox-warmer-arctic- may-mean-colder-winters-for-some

See more at:

When we talk about changes in climate, we need to discuss this as a change from the global average. For instance, we often refer to a deviation from global mean temperature. The article, referred by the website above, written on Dec 13, 2010, tells us an interesting story and offers insight about why we need to discuss this with the global average – please go to the web link to learn more about this. We will re-visit this topic later this semester.

Quote: “This pattern is kind of like leaving the refrigerator door ajar - the refrigerator warms up, but all the cold air spills out into the house.”

As Polar Vortex Stirs, Deep Freeze Threatens U.S. and Europe By Brian K Sullivan, Bloomberg.com January 10, 2021 “The icy blasts threatening to sweep across North America, Europe and Asia starting in late January are from the same weather pattern that triggered the 2014 cold snap known as the polar vortex…”

Climate change and Weather are not the same!

Important facts. Climate is not equal to weather.

Weather – day to day, week to week synoptic change

Climate – average condition of 3 decades or more

Two key ideas for this course: 1st: Climate is regulated by complex interactions amongst different components of the Earth’s system. 2nd: Understanding climate change can be reduced to understanding how “the control knobs” function.

https://www.washingtonpost.com/climate-environment/interactive/2021/2020-tied-for-hottest-year-on- record/?utm_campaign=wp_energy_and_environment&utm_medium=email&utm_source=newsletter&wpisrc=nl_gr een

Global temperatures through 2020

Here we see changes in mean global temperature from 1880 to 2020. The numbers are shown in “anomaly”, which is a deviation from long-term mean value.

University of East Angria Climatic Research Unit: Data https://crudata.uea.ac.uk/cru/data/temperature/

Global temperatures and carbon dioxide through 2009 https://science.sciencemag.org/content/302/5651/1719

Union of Concerned Scientists

Further reading (Massachusetts – Confronting Climate Change in the U.S. Northeast): https://www.cityofboston.gov/images_documents/MA%20confronting%20climate%20 change%20in%20US%20Northeast_tcm3-19616.pdf

Further reading (What Climate Change Means for Massachusetts, 2016): https://19january2017snapshot.epa.gov/sites/production/files/2016- 09/documents/climate-change-ma.pdf

Recently, there have been outbreaks of mosquito related diseases during the summer in New England. These diseases were typically limited the southern states for a long time, however, may now be our new norm given recent changes in the northern climate. Who would have imagined that we would encounter these diseases in New England?

Imagine you have a fever for the first time.

How will your body respond?

Knowing you have a history of fevers and chills, you know how to deal with the symptoms.

That experience/history is important to your response!

Epica Community, 2006

This figure shows reconstructed temperature and atmospheric CO2 concentration variations over the past 800,000 years. Such reconstructed values are based upon CO2 concentration and other “proxy” records retrieved from Antarctic ice cores.

There are periodic ups and downs throughout the interval – natural cycles. Throughout this time interval, CO2 concentrations are always somewhat below 300 ppm except for the past couple hundred years, which both CO2 concentrations and temperature are rising abruptly with unprecedented speed!

What is the current atmospheric CO2 concentration? On May 2013, the concentration almost exceeds the historical milestone of 400 ppm. As you can see from the figure, almost 30 % higher than the highest CO2 concentration for the past 800,000 years, and this increase occurred rather abruptly, just within a couple hundred years. Check (http://co2now.org) for the current CO2 concentration in the atmosphere.

Trends in atmospheric CO2 https://www.esrl.noaa.gov/gmd/ccgg/trends/

I’d like to end this lecture with a quote from Thomas Edison. The idea of exploring alternative sources of energy was already spread in the 1930s.