discussion 4/24 climate patterns & climate change
TRANSCRIPT
![Page 1: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/1.jpg)
Discussion 4/24
Climate patterns & climate change
![Page 2: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/2.jpg)
THE CHANGING CLIMATE
• Climate involves more than just the atmosphere.• Climate may be broadly defined as the long-term
behavior of global environmental system • “To understand fully and to predict changes in the
atmospheric component of the climate system. one must first understand the sun, oceans, ice sheets, solid earth, and all forms of life"
• Thus we talk about a climate system consisting of the atmosphere, hydrosphere, solid earth, biosphere and cryosphere.
• Climate system involves the exchange of energy and moisture among these components
![Page 3: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/3.jpg)
Fig. 14-3, p. 414
![Page 4: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/4.jpg)
![Page 5: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/5.jpg)
Fig. 14-2, p. 413
World map of the Kopper climate classification scheme
![Page 6: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/6.jpg)
Fig. 14-3, p. 414
![Page 7: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/7.jpg)
Highland climate (H)
![Page 8: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/8.jpg)
DETECTING CLIMATE CHANGE
• DIFFICULT TO DETECT CLIMATE CHANGE EXCEPT OVER LONG PERIODS OF TIME.
• INSTRUMENTAL RECORDS GO BACK ONLY A COUPLE OF CENTURIES. THE FURTHER BACK, THE LESS RELIABLE ARE THE DATA.
• SCIENTISTS MUST DECIPHER CHANGES FROM INDIRECT EVIDENCE
• HISTORICAL DOCUMENTS• TREE RINGS• POLLEN RECORDS• GLACIAL ICE – AIR BUBBLES AND DUST• SEA-FLOOR, MATINE SEDIMENTS. OXYGEN
ISOTOPE RATIOS IN FOSSIL SHELLS• FOSSIL RECORDS
![Page 9: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/9.jpg)
CLIMATE CLUES
![Page 10: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/10.jpg)
POLLEN RECORDS
• Pollen degrades slowly and each species can be identified by the shape of its pollen
• Radioactive carbon dating gives the age of the pollen.
• As the climate changes, different types of species become dominant
• Hence the pollen record can be used to identify the type of climate that existed
![Page 11: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/11.jpg)
POLLEN RECORDS
![Page 12: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/12.jpg)
ICE SHEETS• Each year snow falls on the ice sheets and
glaciers. As it accumulates it compresses and traps air bubbles.
• These bubbles of air trapped in ice can be analyzed to determine atmospheric composition.
• Glaciers that exist today can hold bubbles that are tens or hundreds of thousand of years old.
• Dust in the ice sheets can be caused by climate-changing volcanoes, or dry windy conditions that lead to soil erosion.
• Find that the colder periods of the Earth history (20000, 60,000 and 100,000 years ago) are usually much dustier
![Page 13: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/13.jpg)
Fig. 14-18, p. 426
Concentration of Carbon Dioxide and Methane determined from air bubbles in ice cores.
![Page 14: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/14.jpg)
MARINE SEDIMENTS/FOSSIL RECORDS• Foraminifera are micro-organisms that live in the sea
and have a calcium carbonate shell. CaCO3
• As the foraminifera die they sink to the ocean floor to form chalk deposits.
• Among these chalk deposits one also find fossil shells.
• Oxygen has two isotopes which have an atomic mass of 16 and 18
• The ratio of these two isotopes in the shells and foraminifera is a function of the sea temperature
• Fossils reveal ancient animal and plant life that can be used to infer climate characteristics of the past
![Page 15: Discussion 4/24 Climate patterns & climate change](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649e225503460f94b0fd28/html5/thumbnails/15.jpg)
NATURAL CAUSES OF CLIMATE CHANGE
• UNRELATED TO HUMAN ACTIVITY. • VOLCANIC ACTIVITY• ASTEROID IMPACTS• SOLAR VARIABILITY• VARIATIONS IN THE EARTH'S ORBIT• PLATE TECTONICS• CHANGES IN THE OCEAN CIRCULATION PATTERNS