geo 458: climatic change
TRANSCRIPT
![Page 1: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/1.jpg)
Climate: Present, Past & Future….Geo 458: Climatic Change
![Page 2: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/2.jpg)
Geo-Sci 458: Climatic Change
This class will primarily focus on human-induced (anthropogenic) climate change. It will therefore predominantly considercurrent and future climate change, as well as issues concerning emissions, and mitigation and adaptation strategies.
We will review past (paleoclimatic) climate change only in so far as it is necessary to put current and future climate change into a long-term perspective. Natural (volcanic, solar, orbitally driven) climate change is not the main focus of this class. We will deal with climate modelling as necessary to understand the issues related to climate forcing and simulations of future climate changes.
GEO-SCI 658 (Fall semester) Paleoclimatology (Bradley)GEO xxx Climate Modeling (Deconto)
If you are specifically interested in past (natural) climate change, or modelling consider:
![Page 3: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/3.jpg)
INSTRUCTORS: Introduction
Prof. Raymond Bradley ([email protected])
Tel: 545-2120
Office: Morrill II, Room 138A
Dr Ambarish Karmalkar ([email protected]):
Almost-Dr Nick Balascio ([email protected])
Tel: 545-1755
Offices: Hasbrouck [North] Rooms 235 & 236
[Climate System Research Center]
All Office Hours: By appointment
Geo-Sci 458: Climate Change
![Page 4: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/4.jpg)
This course focuses on the Science of Climate Change –highlighting what is known and what remains uncertain. The goal is to encourage you to debate the issue actively and critically, both verbally and in writing.
The first part of the semester (weeks 1-9) is planned and organized in detail. It will entail lectures on causes, impacts, adaptation and mitigation of climate change
The second part of the semester (weeks 10-13) will be “seminar-style” with assigned reading of relevant papers, and discussion of topics related to climate change.
The third part of the semester (weeks 13-16) features in-class presentations of the research projects.
Geo-Sci 458: Climate Change: Synopsis
![Page 5: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/5.jpg)
REQUIRED TEXTBOOK
Sir John Houghton (2004)
“Global Warming,
The Complete Briefing, 4th Edition”.
Course Web site:http://www.geo.umass.edu/courses/geo458
![Page 6: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/6.jpg)
RESEARCH PROJECT
The research project represents the core of this course. It allows you to express your advanced knowledge and research on a pre-approved topic relating to climate change. These projects have to include an in-depth literature review, if possible some original data analysis, and a discussion!
The Research Project consists of two parts:
1. Research paper of not more than 20 pages, written journal-style.
2. Oral presentation to the class during last weeks of the semester (maximum 20 minutes, using PowerPoint or similar software).
Geo-Sci 458: Climate Change: Research Project
![Page 7: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/7.jpg)
Possible Topics for the Research Project
Your own previous research related to climate change (thesis, field work)
• Climate Change and solar variability
Climate Change and energy (fossil fuels, renewable energy sources)
• Climate Change and glaciers
• The Kyoto Protocol (what, why, how?)
• The U.S. government policy on Climate Change: What is it?
UMASS energy use and mitigation strategies
• Climate Change and rising sea level
• Climate Change and extreme events (e.g. floods, droughts, heat waves)
• Climate Change and natural hazards
Post-Kyoto plans
![Page 8: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/8.jpg)
Evaluation will be based on effort, content, accuracy, creativity and writing ability.
Every effort should be made for a concise presentation that demonstrates advanced knowledge of the selected topic.
That means you need to read a lot about the subject before you write anything!
Important Deadlines:
Tuesday, March 9th Project Proposals due
Tuesday, April 20th Start of In-class Presentations
Tuesday, May 4th Project Papers due (No excuses!)
Geo-Sci 458: Climate Change: Research Project
![Page 9: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/9.jpg)
![Page 10: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/10.jpg)
Climate change is in part attributable to human activities. It
is an issue of concern because of its potentially escalating
and far-reaching impacts. This has brought the topic of
climate change and “Global Warming” very much into the
public eye and to the forefront of political debate.
Misunderstanding and/or misrepresentation of the science
often characterize the public and political debate. There is
clearly a need for a wider understanding of the science and
its inherent limitations.
Geo-Sci 458: Climate Change: Synopsis
![Page 11: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/11.jpg)
![Page 12: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/12.jpg)
Senator James Inhofe(R-Oilahoma)
“The threat of catastrophic global warming is the greatest hoax ever perpetrated on the American people … man-induced global warming is an article of religious faith…”
![Page 13: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/13.jpg)
![Page 14: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/14.jpg)
For accurate information about climate change & global warming, see:
http://www.realclimate.org
![Page 15: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/15.jpg)
How would you construct a record of average global temperature?
What are some of the problems that must be accounted for?
![Page 16: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/16.jpg)
![Page 17: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/17.jpg)
“HADCRU”
NASA-GISS
![Page 18: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/18.jpg)
Trend in surface temperature: 1901-2005
Source: After Smith & Reynolds, 2005
![Page 19: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/19.jpg)
![Page 20: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/20.jpg)
![Page 21: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/21.jpg)
JANUARY 21st
![Page 22: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/22.jpg)
![Page 23: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/23.jpg)
390
![Page 24: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/24.jpg)
![Page 25: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/25.jpg)
External forcing
The climate system
![Page 26: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/26.jpg)
Carbon Dioxide (CO2) is a colorless, odorless gas consisting of molecules of two oxygen atoms and one carbon atom. Carbon dioxide is produced when an organic carbon compound (such as wood) or fossilized organic matter (such as coal, oil, or natural gas) is burned in an excess of oxygen. Carbon dioxide is removed from the atmosphere by carbon dioxide "sinks" such as absorption by seawater, and photosynthesis by ocean-dwelling plankton and land plants, including forests and grasslands. However, seawater also releases CO2 to the atmosphere, as do land plants and soils when CO2
is released through respiration.
CO2
![Page 27: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/27.jpg)
Source: NOAA ESRL/GMD
![Page 28: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/28.jpg)
Reconstruction of a Carboniferous (305 million old) coal swamp based on fossil material from the Calhoun coal of Illinois. Illustration by Mary Parrish under the direction of Tom L. Phillips, University of Illinois, and Bill DiMichele, Department of Paleobiology, Smithsonian Institution.
![Page 29: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/29.jpg)
![Page 30: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/30.jpg)
Source: NOAA ESRL/GMD
![Page 31: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/31.jpg)
![Page 32: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/32.jpg)
Source
Source
Sink
Sink
Source: NOAA ESRL/GMD
ALL LAND AREAS
ALL OCEAN AREAS
![Page 33: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/33.jpg)
Source: NOAA ESRL/GMD
“Extra-Tropical”Oceans
Tropical Oceans
![Page 34: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/34.jpg)
North American net carbon flux 2001-2005
Source: Peters et al., 2007
“…the terrestrial biosphereabsorbed 0.65 PgC/yr (1 petagram 1015 g) averaged over the period studied, partly offsetting the estimated 1.85 PgC/yr released by fossil fuel burning and cement manufacturing.”
SINK SOURCE
gC/m2/yr
![Page 35: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/35.jpg)
Source: Peters et al., 2007
But there are large inter-annual variations…: Drought year
gC/m2/yr
![Page 36: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/36.jpg)
…and large intra-annual variations…
Source: NOAA ESRL/GMD
![Page 37: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/37.jpg)
A pulse of CO2 added to the atmosphere by burning fossil fuels decays rapidly at first, with about half of the CO2 taken up by sinks, principally the ocean, within the first quarter century. However, uptake slows as the CO2 added to the ocean exerts a back-pressure on the atmosphere. Even after 1000 years almost one-fifth of the increase due to the initial pulse is still in the atmosphere.
Source: Hansen 2006
![Page 38: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/38.jpg)
Source: Solomon et al., 2009
![Page 39: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/39.jpg)
390
![Page 40: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/40.jpg)
Ice core recovered from Quelccaya Ice Cap
![Page 41: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/41.jpg)
Snow
Ice
Firn
![Page 42: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/42.jpg)
Dome C Antarctica (EPICA site)
(75°06’S, 123°21’E, 3233 m asl)
![Page 43: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/43.jpg)
National Ice Core Laboratory [NICL], Denver
![Page 44: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/44.jpg)
Source: Houghton et al., 2001
Homo sapiensHomo erectus January 19th, 2010:390ppm
180ppm
280ppm
Blue=CO2 (carbon dioxide)
Red=CH4 (methane)
Hundreds of thousands of years before today
![Page 45: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/45.jpg)
Source: Houghton et al., 2001
Homo sapiensHomo erectus
180ppm
280ppm
Blue=CO2 (carbon dioxide)
Red=CH4 (methane)
Hundreds of thousands of years before today
January 19th, 2010:390ppm
~760ppm
![Page 46: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/46.jpg)
Source: Raynaud et al., 2003
Key dates:
1. James Watt’s invention of the steam piston engine in 1784
360
![Page 47: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/47.jpg)
Source: Raynaud et al., 2003
Key dates:
1. James Watt’s invention of the steam piston engine in 1784
2. Karl Benz and Gustav Daimler’s introduction of the first petrol-driven internal combustion engines in 1886
360
![Page 48: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/48.jpg)
1769
James Watt
The start of the Industrial Revolution…The steam engine was invented, powered by
![Page 49: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/49.jpg)
The first stream train—Stephenson’s “rocket”
The Stockton & Darlington Railway’s first steam locomotive, Locomotion No 1, was built by Robert Stephenson & Co. in 1825.
© Science Museum/Science Museum and Society Picture Library
![Page 50: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/50.jpg)
1886:First Daimler car
1886:First Benz car
![Page 51: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/51.jpg)
Source: Raynaud et al., 2003
Key dates:
1. James Watt’s invention of the steam piston engine in 1784
2. Karl Benz and Gustav Daimler’s introduction of the first petrol-driven internal combustion engines in 1886
390
360
![Page 52: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/52.jpg)
Today there are ~6.3B people, & our impact on the planet is ubiquitous…
![Page 53: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/53.jpg)
World population is currently increasing by 240,000 per day….
![Page 54: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/54.jpg)
Number of years to add each billion Year
Ninth
Eighth
Seventh
Sixth
Fifth
Fourth
Third
Second
First Billion All of Human History
1800
130 193030 1960
14 197413 1987
12 1999
14 201315 2028
26 2054
Sources: Population Reference Bureau; UN World Population Prospects (1998)
![Page 55: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/55.jpg)
Today…
1.4B cattle….with a global impact on CH4 levels…
SO2 release is ~160Tg yr-1…~2x all natural emissions…
More N2 fixed synthetically & applied as fertilizer than is fixed naturally in all terrestrial ecosystems…
Half of all accessible freshwater is used by mankind…impacts on rivers, groundwater….depletion & contamination…
![Page 56: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/56.jpg)
Species extinction rate has increased by orders of magnitude within the last 200 years…
Toxic substances contaminate many regions…
Man-made gases have depleted stratospheric ozone levels…
Vast quantities of fossil carbon are returned to the atmosphere each year (~6.3 Gt/C yr-1)
CO2 radiative forcing is now ~1.5W m-2
![Page 57: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/57.jpg)
The Anthropocene Age:
A Human-dominated geological episode…with a global imprint
P. Crutzen & E. Stoermer, 2000
![Page 58: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/58.jpg)
Methane (CH4) is a colorless, odorless non-toxic gas consisting of molecules of four hydrogen atoms and one carbon atom. Methane is combustible, and mixtures of about 5 to 15% in air are explosive. It is the main constituent of natural gas, a fossil fuel, and it is released when organic matter decomposes in environments lacking sufficient oxygen.Natural sources include wetlands, swamps and marshes, termites, and oceans.Man-made sources include the mining and burning of fossil fuels, digestive processes in ruminant animals such as cattle, rice paddies and the buried waste in landfills. Most methane is broken down in the atmosphere by reacting with small very reactive molecules called hydroxyl (OH) radicals.
CH4
![Page 59: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/59.jpg)
Nitrous oxide (N2O) is a colorless, non-flammable gas with a sweetish odour, commonly known as "laughing gas", and sometimes used as an anaesthetic. Nitrous oxide is naturally produced in the oceans and in rainforests. Man-made sources of nitrous oxide include nylon and nitric acid production, the use of fertilizers in agriculture, cars with catalytic converters and the burning of organic matter.
Nitrous oxide is broken down in the atmosphere by chemical reactions that involve sunlight.
N2O
![Page 60: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/60.jpg)
![Page 61: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/61.jpg)
JANUARY 26th
![Page 62: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/62.jpg)
![Page 63: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/63.jpg)
How have these global changes affected the Arctic?
-Sea-ice-Glaciers & ice sheets
-Biology
![Page 64: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/64.jpg)
August Arctic Ocean Ice Extent
Source: NSIDC
![Page 65: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/65.jpg)
Mid-Sept 2005
Mid-Sept 2007
![Page 66: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/66.jpg)
Source: NASA
For the first time, both Northeast and Northwest Passages were open to shipping in 2008
![Page 67: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/67.jpg)
Source: S. Borgerson 2008
Yokohama to Rotterdam
![Page 68: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/68.jpg)
![Page 69: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/69.jpg)
![Page 70: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/70.jpg)
Not only has overall area of Arctic sea-ice declined, but thickness and extent of multi-year ice has been greatly reduced
![Page 71: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/71.jpg)
![Page 72: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/72.jpg)
![Page 73: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/73.jpg)
Mid-Sept 2005
Mid-Sept 2007
Siberia
Siberia
Greenland
Greenland
Alaska
Alaska
Declining sea-ice extent & thickness
over the Arctic Ocean
![Page 74: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/74.jpg)
![Page 75: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/75.jpg)
Polar bear populations vary widely across the Arctic. Longest studies have been in Hudson’s Bay
![Page 76: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/76.jpg)
189kg
Western Hudson Bay ice breakup
Mean body weight of lone* female polar bears
Reproduction unsuccessful…
Source: Stirling & Parkinson 2006*assumed to be pregnant
Sea-ice cover breakup is ~7 days earlier per decade
![Page 77: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/77.jpg)
![Page 78: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/78.jpg)
Hubbard Glacier, Alaska
![Page 79: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/79.jpg)
![Page 80: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/80.jpg)
Global mean sea-level change since 1870
~20cm (8 inches)
![Page 81: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/81.jpg)
Source: UNEP-GRID, ARENAL
![Page 82: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/82.jpg)
![Page 83: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/83.jpg)
![Page 84: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/84.jpg)
![Page 85: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/85.jpg)
Quelccaya Ice Cap, SE P
![Page 86: Geo 458: Climatic Change](https://reader030.vdocument.in/reader030/viewer/2022020701/61f800cf11ff8f2f3557cbee/html5/thumbnails/86.jpg)
Electricity from hydro-electric power
Bolivia 50%Colombia 73%Ecuador
72%Peru 81%