Weather, climate and climate changelecture before group exercise

Ch. 20, sections 20.1, 20.4. Review

sections 18.2 and fig. 18.7

What is weather?

• State of the atmosphere at any given time

• Weather is: temperature, humidity, type and amount of cloudiness, air pressure, speed and direction of wind

Climate and Climate Change

• Climate: aggregate weather conditions; “weather over 30 years”

• NOT an average – must take into account variability and extreme events.

• Sun powers it all.

Climate is an aggregate of weather

• Involves the exchanges of energy and moisture that occur among the • Atmosphere• Hydrosphere• Solid Earth• Biosphere, and• Cryosphere (ice and snow)

Global climate zones

• Climate and biology (biome) complexly intertwined

• Figure 20.8 Global climate zones. Each climate zone supports a unique biome.

• Figure 20.9 A model climograph. This graph shows the average monthly temperature (curved line) and average monthly precipitation for Nashville, TN

Fig. 20-8a, p.488

Fig. 20-8b, p.489

Fig. 20-9, p.490

Fig. 20-10, p.491

Fig. 20-11, p.491

Fig. 20-12, p.492

Climate change: It’s more than average temperature….

What if just winters were warmer?What if winters were the same, summers

much hotter?What if precipitation greatly increased, or

decreased?What if most precipitation fell at one time

of year, say in the winter and spring?

• All of these changes would affect living things

• Esp. crops grown for food, and humans

What’s heating the atmosphere?

• Starts with: solar radiation

• Atmosphere lets most light in (fig. 18.6)

• Some reflected, some absorbed by ground

Greenhouse effect (Fig. 18.7)

1: Earth’s surface absorbs short-wavelength solar radiation (orange lines), and become warmer

• 2: Earth’s surface re-radiates the energy as long-wavelength infrared heat rays

The Greenhouse Effect

• Step 3: Molecules in the atmosphere absorb some of the heat, and the atmosphere becomes warmer.

• CO2, water, others

CO2, Greenhouse Effect, Global Warming

• Today: CO2 concentration in our atmosphere is >0.037 % or 370 PPM

• If less CO2: cooler temperatures and cooler climate

• If more CO2: warmer temperatures and warmer climate

• Industrial Revolution was powered by burning coal and fossil fuels

• Continues today with burning petroleum (fig. 5.30A: energy use in USA, 2000)

Oil and gas

• Oil and gas are hydrocarbons: chains or rings of C and H

• React with O2 to form gas and heat energy

• For example, octane:

• 2 C8H18 + 25 O2 = 16 CO2 + 18 H2O + heat energy

• Example: propane:

• C3H8 + 5 O2 = 3 CO2 + 4 H2O + heat energy

(Slide from February!)

Most up-to-date info

Fig. 21-4, p.503

Pretty clear now:

• There has been an increase in average temperature by 0.3 to 0.6 °C

• Question: “Are these temperature trends caused by human activities or would they have occurred anyway?”

• Given the consequences, can we afford to do nothing?

Local climate change?

• Study local records and plot changes• Keep in mind weather is very variable!• Local area with best long-term records:

Greenville Water plant, Darke Co., OH• Records start in 1887• Source of graph on next slide:

http://cdiac.esd.ornl.gov/cgi-bin/broker?_PROGRAM=prog.climsite.sas&_SERVICE=default&id=333375

Ave. Temp., 1900 - 2002

Is climate change happening here?

• And if not, do we really need to worry?

• Are there other places that show climate changes a bit more clearly?

• And if not, what is the big deal?

Fig. 21-16, p.515

Climate ‘hotspots’

• Areas in the far north and far south are warming up faster than mid-latitudes

• Spring starting early

• Permafrost melting or partially melting

• Southern species spreading northward

Climate ‘hotspots’

• Prep for Friday’s exercise:

• Hay River, NWT, on Great Slave Lake, near Yellowknife.

• Long, nearly complete record of temp and precipitation

Vegetation type: Northern evergreen forest

In area of sporadic permafrost

Ohio Academic Science Standards K-2 Science benchmarks

• Gather & communicate information from careful observations and simple investigation. (Scientific Inquiry)

• Observe, describe and measure changes in the weather, both long term and short term (Earth & Space Science)

Ohio Academic Science Standards 3 – 5 Science benchmarks

• Analyze weather and changes that occur over a period of time (Earth & Space Science)

• Organize and evaluate observations, measurements, and other data to formulate inferences and conclusions. (Scientific Inquiry)

• Use results and data from investigations to provide the evidence to support explanations and conclusions.(Scientific Inquiry)

Ohio Academic Science Standards 3 – 5 Science benchmarks

• Distinguish between fact and opinion and explain how ideas and conclusions change as new knowledge is gained. (Scientific Ways of Knowing)

• Explain the importance of keeping records of observations and investigations that are accurate and understandable. (Scientific Ways of Knowing)

Ohio Academic Science Standards 6 - 8 Science Benchmarks

• Describe interactions of matter and energy throughout the lithosphere, hydrosphere & atmosphere (e.g. water cycle, weather, etc.)

Ohio Academic Science Standards 6 - 8 Science Benchmarks

• Analyze and interpret data from scientific investigations using appropriate mathematical skills in order to draw valid conclusions. (Scientific Inquiry)

• Use skills of scientific inquiry processes. (e.g. hypothesis, record keeping, description and explanation)(Scientific Ways of Knowing)

Ohio Academic Science Standards 9 - 10 Science Benchmarks

• Explain that many processes occur in patterns within the Earth’s systems. (Earth & Space Science)

• Summarize the historical development of scientific theories and ideas, and describe emerging issues in the study of Earth and space sciences. (Earth & Space Science)

Ohio Academic Science Standards 9 - 10 Science Benchmarks

• Explain that scientific knowledge must be based on evidence, be predictive, logical, subject to modification and limited to the natural world. (Scientific Ways of Knowing)

• Explain how scientific inquiry is guided by knowledge, observation, ideas, and questions. (Scientific Ways of Knowing)

Ohio Academic Science Standards 11 -12 Science Benchmarks

• Describe how Earth is made up of a series of interconnected systems and how a change in one system affects other systems. (E&SS)

• Explain that humans are an integral part of the Earth’s system and the choices humans make today impact natural systems in the future. (E&SS)

• Summarize the historical development of scientific theories and ideas, and describe emerging issues in the study of Earth and space sciences. (E&SS)

Ohio Academic Science Standards 11 -12 Science Benchmarks

• Predict how human choices today will determine the quality and quantity of life on Earth. (Science & Technology)

• Explain how scientific evidence is used to develop and revise scientific predictions, ideas, or theories. (Scientific Ways of Knowing)