Discussion 1Years of Living Dangerously Season 2 Episode 2
This documentary television series shows 1) real estate in Miami under the context of climate change and 2) what climate/paleoclimate scientists are actually doing in the field under extreme conditions and in the lab. Numerous well-known scientists share their enthusiasm about their research and explain their cutting-edge research in unique areas ranging from the tropical oceans to deep sea. Watch the video and answer the following two questions. Respond to at least two peer postings. Due by February 11th.
The link to the video can be found below
https://login.silk.library.umass.edu/login?qurl=https://fod.infobase.com%2fp_ViewVideo.aspx%3fxtid%3d138065
Cite at least 4 sources from credible sources
Arctic Climate Change
The difference during summer
is increasing as the sea ice
extension is decreasing in
relation to the recent past.
http://nsidc.org/arcticseaicenews/
In lecture 1, we learned about the seasonal migration of Arctic
sea ice extension. In this figure, it is very clear that
20
12 was
exceptional because the Arctic sea ice during that summer was
at the greatest minimum ever observed, dropping far below the
mean of the long term trend. Let’s take a look what happened
after, particularly in 2016.
(National Snow and Ice Data Center)
This figure is based on a report of sea ice extension in November
2016. At the end of summer in 2016, the minimum sea ice
extension was the second lowest after the 2012 extension (left
red arrow). As the season migrates and turns colder, the sea ice
did not grow back as fast as it should have relative to all
previously measured patterns (right red arrow). By November, the
sea ice extension was the lowest ever recorded in November.
What was happening in 2016?
Daily mean temperatures for the Arctic area north of the
80th northern parallel. (Danish Meteorological Institute)
Arctic temperatures are about 20 degrees Celsius higher than normal
above 80 degrees North Latitude! (Nov 2016).
This figure shows daily temperature measurements in the Arctic at 80 degrees north in
2016 (red line) along with a computer simulation of temperature patterns based on long-
term temperature measurements of the Arctic region (green line). The blue line is the
point of freezing (0 degree Celsius). Please note that Y-axis identifies temperature shown
in units Kelvin (K). Kelvin is a commonly used unit of measurement in science for
temperature. Please see the following slide for more detail. The X-axis identifies the
number of days in 2016. For example, the day 1 indicates January 1st, and the day 365
equates to December 31st.
As you can see, there is seasonal variation. You will also notice that, most of the year, the
temperature remains below the freezing level (blue line), although it will slightly exceed
freezing for a short period of time during summer. In November of 2016, the temperature
north of 80 degrees latitude was around -5 degrees C. This is below freezing (not by
much), but is anomalous to the normal temperature of around -25 degrees C (see vertical
blue dashed line). The temperature difference between the long term mean (green line)
and the observed temperature (red line) was as great as 20 degrees!!
(continue)
(continued)
Why was this happening? Why did it happen in the Arctic? This phenomenon is
known as polar amplification and it is important that we learn about this
concept to understand how and why changes in our climate system affect
different parts of the world unequally. For now, maintain an awareness of polar
amplification as we will learn more about this concept in the following weeks.
In the meantime, please take a moment to think about whether such daily
temperature changes north of 80 degrees latitude are considered “climate” or
“weather”?
Further, please check the latest news from Arctic Sea Ice News and Analysis for
additional information: https://nsidc.org/arcticseaicenews/
A recent science study reports that
rapid warming in the Arctic is a likely
driver of the recent extreme winter
weather in the US.
https://www.science.org/doi/10.11
26/science.abi9167?utm_campaign
=SciMag&utm_source=Social&utm_
medium=Twitter
https://nsidc.org/arcticseaicenews/
https://www.science.org/doi/10.1126/science.abi9167?utm_campaign=SciMag&utm_source=Social&utm_medium=Twitter
Fahrenheit is a temperature scale based on one proposed in
17
24 by the
German physicist Daniel Gabriel Fahrenheit. 0 F was the lowest temperature
Dr. Fahrenheit could measure, 100 F is the average human core body
temperature. In scientific measurement, Kelvin is more common because by
definition 0 Kelvin is called absolute zero. Absolute zero is theoretically the
lowest possible temperature where all molecules seize their motion (almost no
heat is emitted by the molecule). In this slide, temperatures in Fahrenheit,
Kelvin, and Celsius are compared in the same scale.
Weather Forecasting
• Weather affects nearly everyone, every day.
• Weather forecasts are issued:
o To save lives
o Reduce property damage
o Reduce crop damage
o To let the general public know what to expect
• Forecasts are often utilized to make many important decisions on
a daily basis
• So how is it done, and how is it done correctly?
National Weather Service Mission:
• The NWS provides weather, hydrologic, and climate
forecasts and warnings for the US, its territories,
adjacent waters, and ocean areas for the protection
of life and property and the enhancement of the
national economy.
Tools available to a forecaster…
• Weather Observations
(including surface data, satellite data, and radar data)
• Commercial aircraft data
• Wind profilers
• Numerical Model Output
…There are a lot of sources for data!
Forecasting technique – Persistence
13Image from WW2010 Online Guide
The most primitive method of forecasting is to observe and estimate that
there will be no changes to the present. Today is sunny, therefore, tomorrow
will also be sunny. This may work relatively well in a dry and arid region, but
does it work in the New England region? Probably not.
The Trend Technique
15Image from Meteorology Today by C. Donald Ahrens
Another method of forecasting that has been used in the more recent past is to
understand trends. As we all know, however, weather systems migrate from west
to east in the mid latitude, where we live, due to prevailing wind called the
westerly (we will cover this in the following weeks). The atmospheric pressure
system, in general, crosses over North America in 3 to 5 days. With this, the
system travels approximately 800 miles per day. With this understanding, we can
broadly predict when a storm will approach a specified region. Can this be used
to make an accurate prediction? Although this maybe not be a desirable way to
forecast for a long-term period, it may work for a shorter and current time
interval.
The Analogue Technique
17
The analogue technique is a combination of climate and weather. Based on long-
term observations, you might be able to identify a clear pattern in the
atmospheric system. For instance, you may notice that, statistically, when a dry
and cold weather pattern is observed in the northwest (high pressure system),
there is a tendency for stormy weather in the northeast (low pressure system).
This method could be useful and may produce relatively reliable results for
slightly longer time periods (few days to a week).
Accuracy and skill in forecasting
After you learn about forecasting techniques, you may be asking yourself
– what is an ”accurate” forecast?
• What is an accurate forecast?
o Your forecast for tonight’s minimum temp is 0F
If the actual minimum was 1F, is it inaccurate??
If the actual minimum was 10F, is it inaccurate??
o Accuracy (in forecasting) is arbitrary and relative – it is not
clearly or objectively defined.
19
Modern weather forecasts are based on model
forecasts
– Numerical Weather Prediction
In order to increase accuracy, we heavily rely on numerical weather prediction.
• Predict the state of the atmosphere (e.g., pressure,
temperature, precip, winds, etc) in time
• Use mathematical equations – initialized with observational
data
…Why are models often wrong?
20
Problems with numerical modeling
21
• Models represent a “simplified” atmosphere – not every real
process in atmosphere can be resolved in models.
• Many are not global in coverage
• The initial atmospheric state is not well-known
• The data may also have errors in it
• The model equations compute quantities at grid points (30-
50km).
• The atmosphere is fundamentally chaotic!
So, the atmosphere is fundamentally chaotic and this is why weather
forecasting, although state of the art, is still not perfect. Therefore, in order
to understand the climate system, scientists focus on key phenomena and/or
relationships that effectively control or alter the climate system of the Earth.
Here, we call them the “climate knobs” and let’s talk more about it in the
next lecture.
Here is a news from weather forecast development:
Artificial Intelligence May Be Key to
Better Weather Forecasts
Recent advances in machine learning
hold great potential for converting a
deluge of data into weather forecasts
that are fast, accurate, and detailed.
By Sid-Ahmed Boukabara, Vladimir
Krasnopolsky, Jebb Q. Stewart, Stephen
G. Penny, Ross N. Hoffman, and Eric
Maddy, 1 August 2019
Artificial Intelligence May Be Key to Better Weather Forecasts
mailto:sid.boukabara@noaa.gov
Artificial Intelligence May Be Key to Better Weather Forecasts
https://www.ncdc.noaa.gov/billions/overview
“In 2021, there were 20 weather/climate disaster events with losses exceeding $1 billion each
to affect the United States.” “Overall, these events resulted in the deaths of 688 people and
had significant economic effects on the areas impacted.”
https://www.ncdc.noaa.gov/billions/overview
https://www.noaa.gov/news/2021-was-worlds-6th-
warmest-year-on-record
2021 was world’s 6th-warmest year says NOAA
https://medialibrary.climatecentral.org/resources/2020-in-review-global-temperature-rankings
– Could we have predicted that 2021
would become the 6nd warmest year on
record or predict what 2022
temperatures will look like when the
report becomes available? The answer
is no. However, you can look into the
long-term trend and anticipate what
likely will happen in the future!
(weather vs climate)
https://www.noaa.gov/news/2021-was-worlds-6th-warmest-year-on-record
https://medialibrary.climatecentral.org/resources/2020-in-review-global-temperature-rankings
Please take a moment to read the article published in March 2017 about our
perceptions of climate change. This was before the catastrophes caused by Hurricane
Harvey and Hurricane Irma in 2017.
How Americans Think About
Climate Change, in Six Maps
By NADJA POPOVICH, JOHN SCHWARTZ
and TATIANA SCHLOSSBERG
MARCH 21, 2017
https://www.nytimes.com/interactive/201
7/03/21/climate/how-americans-think-
about-climate-change-in-six-maps.html
https://www.nytimes.com/interactive/2017/03/21/climate/how-americans-think-about-climate-change-in-six-maps.html
Example Test 1 question:
Climate differs from weather in that
A. climate is a broad composite of temperature
conditions, while weather addresses temperature
as well as precipitation, snow and ice cover, and
wind conditions.
B. climate change occurs over longer durations than
do weather changes.
C. climate change is exclusively global, whereas
weather is exclusively regional.
D. climate and weather do not differ, they are
interchangeable terms.
At last, here is an example questions in preparation for the test. The
questions in test 1 will be similar in format to this question, but not
necessarily the same question.
The answer is B.
This is likely to be one of the most well-cited pictures of Earth called “Blue
Marble”. It was taken on December 7, 1972, by the crew of the Apollo 17
spacecraft. It has a distinct color of blue, because the Earth uniquely carries
an atmosphere and 70% of the Earth’s surface is covered by the ocean.
Atmosphere from Space
We can see our atmosphere even from space. In this figure, the bright layer is
the atmosphere between space and Earth; both are shown here in black.
Please note how thin the atmospheric layer is relative to Earth’s diameter!
Another view
of the
Atmosphere
from Space
This is a zoomed-in image of the atmosphere. You will notice that there is a
gradual color change ranging from a brownish color closer to the Earth’s
surface that transitions to a pale blue and eventually fades into space. The
atmosphere extends about 10,000km into space. There is no exact top to the
atmosphere. Due to the Earth’s gravity, the number of molecules, which
individually each carry mass, gradually decreases outward into space. Most of
the gas molecules are within the lower atmosphere. 90% of the atmosphere’s
mass is in its lower 10km and 99.9997% is within the lower 100km. You will
also notice that there are little blobs in the brownish colored layer close to the
surface. This layer is called the troposphere, the lowest layer of the
atmosphere ranging from 6-10km above sea level. This is where we live,
clouds are formed, daily weather is observed, and the majority of the
molecules exist. The blobs you see are seemingly giant cumulonimbus – dense
towering clouds – often associated with thunderstorms.
Composition of the Atmosphere including
variable
components
(by volume)
The three elements that make up over 99.9% of the atmosphere – nitrogen,
oxygen, and argon. These elements are abundant in the atmosphere and have
many uses.
Pure nitrogen (N2) is used in its very cold, liquid state as it boils at -195.8 C (or
-320F). Ted Williams, a baseball player who played for the Boston Red Sox for
22 years, and deceased in 2002, is preserved in liquid nitrogen since his family
members chose to have his remains frozen.
Pure oxygen (O2) is used to achieve higher temperatures, to increase the
efficiency of waste incinerators. It is also used as an oxidizing agent, and in
medical applications to assist and sustain a person’s respiratory functions.
Argon (Ar) is a colorless, odorless, nontoxic, and nonreactive gas. It creates
inert environments for growing crystals, often used in semiconductors. It
protects materials against corrosion. It also fills the air space in double-pane
insulating windows.
Earth’s climate system
and interactions of its
components
Two key ideas for this course, especially for the first half is:
1st: Climate is regulated by complex interactions amongst components of
the Earth’s system.
2nd: Understanding climate change can be reduced to understanding
how “the control knobs” function
Climate change
The knobs that control earth’s climate:
• Atmospheric composition (greenhouse effect
)
• Amount of solar radiation (luminosity)
• What parts of Earth get radiation (orbit)
• Atmospheric and ocean circulation
• Earth’s albedo (fraction of solar energy reflected off earth’s
surface)
• Volcanoes
• Plate tectonics
Greenhouse Effect
We are here.
First, a bit about radiation . . .
How the control knobs work
Amount of energy reaching earth determines the climate. Dominant source
of energy is sunlight, which when reaching Earth can heat the land, ocean,
and atmosphere.
If a chunk of matter oscillates and interacts with light at all possible
frequencies, it is called blackbody. And the light (energy) that is emitted by
a blackbody is called blackbody radiation. In this manner, although
“blackbody” is originally named for an ideal object, we consider the Earth
as a blackbody. In fact, many objects that radiate energy back when they
are heated are considered as a blackbody.
The Greenhouse Effect
Greenhouse gases don’t “trap”
heat; they absorb heat and re-
radiate it out to space and back
to Earth.
So, some of that sunlight is reflected back to space by the Earth’s surface,
clouds, or ice. But much of the sunlight that reaches Earth is absorbed and
warms the planet. When Earth emits the same amount of energy that it
absorbs, its energy budget is in balance, and its average temperature
remains stable.
The discrepancy between incoming solar energy and outgoing radiation
energy is the greenhouse effect. Earth’s atmosphere contains greenhouse
gases (e.g. CO2, CH4, etc.) that absorb 95% of the longwave (we will learn
more about this later) back radiation emitted from the surface.
Earth’s radiation budget
Here is a breakdown of the numbers…
Solar radia)on arriving at the top of Earth’s atmosphere averages 342 W/m2,
indicated here as 100% (upper leB). About 30% of the incoming radia)on is
reflected and scaHered back into space, and the other 240 W/m2 (70%) enters
the climate system. Some of this entering radia=on warms Earth’s surface
and causes it to radiate heat upward (right). The greenhouse effect (lower
right) retains 96% of the heat radiated back from Earth’s heated surface and
warms Earth by 31 C̊.
41
0
http://berkeleyearth.org/2018-
temperatures/
(Upper figure) Mean global air temperature variation from 1850 to 2018
In 2018, 9 of the 10 warmest years have occurred since 1990.
(Lower figure) Atmospheric CO2 variation during the same interval
From 1960 to present: the atmospheric CO2 concentration has been
measured in Mauna Loa, Hawaii. Before 1960, the CO2 concentration is a
reconstructed value based upon CO2 preserved in ice cores.
Ice core records
Temp.
CO2
Dust
Annually
laminated
bands
within ice
core
Thousands of years ago
Why do we use ice core records instead of observed data (which seems to
be the more direct and reliable approach)?
This is because, unfortunately, we only have a limited number of observed
records for us to understand the natural cycle of the Earth’s climate – most
of the data are available only for the past 50 years of which a few extend
past a couple hundred years. This means, for instance, if we would like to
discuss our climate system in relation to the El Nino cycle, which likely
occurs every 3-5 years on average, we can only refer to a few of those
events. For this reason, we need a longer record than the observational
record.
By using ice core records, as shown in this figure, we can study and argue
climate/environmental variability of the past 400,000 years. If the ice core
preserves annual layers (like tree rings), the record you are looking at is
basically a sub-seasonal resolution of climate variability.
Climate Change in New England
Weider and Boutt, 2010
What is happening in New England?
This figure shows 12 month moving averages of temperature data
measured at 43 observational sites across New England between
1920 and 2009. Please note that this data is an average of 12
months, and any seasonal variability is expressed much less obvious.
There maybe a warming trend? This may be correct. However,
importantly, local temperature variability can be quite different from
global temperature variability – it maybe even cooling in some areas.
Receding mountain glacier due to recent warming.
0
1000
2000
3000
4000
5000
6000
7000
1000 1200 1400 1600 1800 2000
P
op
ul
at
io
n
(M
ill
io
ns
)
Time (Years)
World Population (http://www.census.gov/ipc/www/idb/worldpopinfo.html)
1967
1920
1850
Today 7 billion
Is this temperature trend related to population growth?
Popula’on growth
If so, what will the future population be?
Check today’s population:
https://www.census.gov/popclock/
MMD-A1B 2080-2099 vs 1980-1999 IPCC 2007
Effects on Agriculture and the Ocean?
Also figures from the IPCC (Intergovernmental Panel on Climate Change)
showing the discrepancy between simulated climate model results 2080-2099
and observational data 1980-1999. Precipitation, soil moisture, runoff, and
evaporation. Some areas experience drier conditions.
Source: IPCC 2007
Black line: observed temperatures
Blue: expected changes due to natural factors
Pink: expected changes due to natural factors plus greenhouse gases
Comparison of observed continental- and global-scale changes in surface
temperature with results simulated by climate models using either natural or both
natural and anthropogenic forcings. Averages of observations are shown for the
period 1906-2005 (black line) plotted against the center of the decade and relative
to the corresponding average for 1901-1950. Lines are dashed where spatial
coverage is less than 50%. Blue shaded bands show the 5 to 95% range for 19
simulations from five climate models using only natural forcings due to solar
activity and volcanoes. Red shaded bands show the 5 to 95% range for 58
simulations from 14 climate models using both natural and anthropogenic forcings
(like CO2)
Change in Snow Depth CRCM-A2 2070
Results from another climate model showing changes in snow depth in
North America.
An example of a positive feedback
Warming reduces the cover of snow and sea ice in the Arctic from 2005
(right) to 2007 (left), increases the amount of heat absorbed by exposed
water, reduces albedo, and thereby further warms the climate. This is called
a positive feedback process.
We will learn more about “albedo” and “feedback process” later this
semester.
November Arctic Ocean Ice Extent
Source: NSIDC
Monthly November ice
extent for 1979 to 2014
shows a decline of 4.7%
per decade relative to the
1981 to 2010 average.
Source: Steffen et al., 2008
Area of Melting on the Greenland Ice Sheet: increasing
Greenland ice sheet is also increasingly melting from 1979 to 2008.
Maps of maximum annual surface melt on the Greenland Ice Sheet
derived from monthly ice surface temperature product of Greenland
(2000-2016). Greenland ice sheet is also increasingly melBng!
A Multilayer Surface Temperature, Surface Albedo, and Water Vapor Product of
Greenland from MODIS, April 2018, Remote Sensing 10(4):555,
DOI: 10.3390/rs10040555
This figure shows the amount of ice sheet lost in Greenland and Antarctica
between 2002 and 2009.
Velicogna (2009), Geophysical Research Letters, v.36. L19503, DOI: 10.1029GL040222
https://www.antarcticglaciers.org/2020/01/what-is-the-ice-
volume-of-thwaites-glacier/
Ice streams of Antarctica
Recent observations show that
incursions of warm ocean water cause
melting of the undersides of floating ice
shelves in West Antarctica. This could
cause a rapid and irreversible rise in sea
level.
Reference: Hillenbrand, CD., Smith, J., Hodell, D. et
al. West Antarctic Ice Sheet retreat driven by
Holocene warm water incursions. Nature 547, 43–
48 (2017). https://doi.org/10.1038/nature22995
Our own UMass faculty, Prof. DeConto
published in Nature journal in 2021 a
suggestion that if emissions continue at
their current pace, by approximately
2060, the Antarctic Ice Sheet will have
crossed a critical threshold that will
cause irreversible global sea level rise
within a human timescale.
Reference: DeConto, R.M., Pollard, D., Alley, R.B. et
al. The Paris Climate Agreement and future sea-
level rise from Antarctica. Nature 593, 83–89
(2021). https://doi-
org.silk.library.umass.edu/10.1038/s41586-021-
03427-0
https://doi-org.silk.library.umass.edu/10.1038/s41586-021-03427-0
Future Sea Level?
If we lose all ice in the world – what will happen to the sea level?
Bamber et al., 2009
A simula)on model result shows what happens to the sea level, if all sea
ice/con)nental ice (ice sheet) fully collapsed. Most of the northern
hemisphere experiences an increase in sea level of over 1 m.
What happens
with 1 m sea
level rise?
Here are links that include recent research outcome about ice loss from
Earth’s ice sheets. Check out the amazing and disturbing videos in this NASA
briefing….
Snow over Antarctica Buffered Sea Level Rise during Last Century
https://go.nasa.gov/2GeaWZb
Carbon Brief.org
http://www.carbonbrief.org/blog/2015/08/new-nasa-videos-show-stark-ice-
loss-from-earths-ice-sheets/
Annual Arctic sea ice minimum 1979-2018 with area graph
https://climate.nasa.gov/climate_resources/155/video-annual-arctic-sea-
ice-minimum-1979-2018-with-area-graph/
Antarctic ice loss: 2002-2016
https://climate.nasa.gov/climate_resources/154/video-antarctic-ice-loss-
2002-2016/
https://t.co/9metgs5qRp
http://www.carbonbrief.org/blog/2015/08/new-nasa-videos-show-stark-ice-loss-from-earths-ice-sheets/
https://climate.nasa.gov/climate_resources/155/video-annual-arctic-sea-ice-minimum-1979-2018-with-area-graph/
https://climate.nasa.gov/climate_resources/154/video-antarctic-ice-loss-2002-2016/
