Climate Change: Scientific Fact vs. Political Fiction

C. J. Hansen-Koharcheck

The Difference between Climate and Weather

• Weather is what happens on any given day– Sunshine– Hurricanes – Snow– Wind– …

• Climate is the long-term average of atmospheric conditions, usually averaged over 30 years– A consistent increase in the average winter (or summer or

yearly) temperature over a number of years is considered climate change

– The average global temperature has increased 0.5 deg over the last 30 years

Just the Facts…

1. CO2 is a greenhouse gas

2. The amount of CO2 in our atmosphere is increasing

3. We are responsible for the rising levels of CO2

in our atmosphere

Not so clear

• What are the consequences?

1. CO2 is a greenhouse gas

• What is a greenhouse gas?

– A gas which absorbs thermal radiation (heat)

1. CO2 is a greenhouse gas

• How does a greenhouse gas warm the atmosphere?

Other greenhouse gases

• Other molecules:

Our Goldilocks Planet

Venus:Too muchAverage surface

temperature = 864 F

Mars: Too little-80 F

Earth:

Just right

57 F

Currently the earth has just the right amount of greenhouse gases …

The Earth has experiencedClimate Change in the Past

• Much warmer climate millions of years ago

0

2. The amount of CO2 in our atmosphere is increasing

• These are measurements from ice cores• The steep upward trend began around 1850, the

beginning of the industrial revolution

2. The amount of CO2 in our atmosphere is increasing

• These are direct measurements, made in Hawaii since 1958• Last year the level reached 400 ppm

3. We are responsible for the rising levels of CO2 in our atmosphere

Sources of CO2:

• Electricity generation, especially coal-powered power plants

• Transportation

• Industrial sources (manufacturing)

• Agriculture (deforestation)

What is the Evidence for Climate Change?

Evidence for Climate Change

• Thinning of Greenland ice cover

• Retreat of mountain glaciers

• Melting permafrost

• Rising sea levels– From melting ice

But mostly, as water warms it expands

Evidence for Climate Change

• Loss of arctic sea ice• Problem: this will

have feedback consequences– Ice reflects sunlight

back to space– Liquid water absorbs

sunshine and warms up

• Affect on ocean currents?

• Loss of polar bear habitat

Evidence for Climate Change –Flora and Fauna

• Too many to list!

• Shift to timing of life cycle events– Earlier budding of trees

– Bird migration earlier

• Shift to range boundaries– Butterflies have shifted their range 200 km northward in Europe

– Shift of tree lines

– Flagstaff “island in the sky”• Pinion-Juniper –to – ponderosa pine – to – alpine tundra

• Zones defined by altitude, are shifting up

• A local example: Bark Beetles

Bark Beetles

• British Columbia has lost 33 million acres of lodgepole pines

• Colorado and Wyoming have lost > 3 million acres

• Due to drought and bark beetle infestation

• Longer warmer summers -> reproductive cycle reduced from 2 years to 1 year

• Consequence: Risk for forest fires

The Role of Earth’s Oceans

• Earth’s oceans have already absorbed a significant amount of CO2 and heat

• The oceans are more acidic now – with unknown consequences for ocean life

• The oceans are warmer now – displacing species?

• More fresh water introduced at the north pole as the arctic ice sheet melts

• What will be the effect on the oceans’ currents?

• Thermo (temperature) – haline (salt content, which affects density)• The oceans currents are driven by temperature and salt content – both of which are affected by climate change

What are the consequences for the Future?

• This is where the most uncertainty is…

• If the global temperature rises a few degrees is that really so bad?– It’s the energy -> more intense storms

• Too much water in some places, too little in others– Most important resource we need to manage

• Probably the biggest threat is to the world food supply

What will happen in the future?

• Three possibilities

– We stabilize the CO2 levels in our atmosphere

• Consequences we can live with

– We continue to put CO2 into the atmosphere

• Global average temperature will continue to rise

• More severe consequences

– We continue to blithely put CO2 into the atmosphere and trigger a tripping point

• Likely catastrophic for civilization – food supply collapse, political chaos

Mis-information

• “This is a natural phenomena that has happened before”– Yes, but never at this rate

• “China needs to be a part of the solution”– Well yes, but American’s carbon footprint is far higher

per capita than the chinese

• “This is a hoax for scientists to get funding”– We need scientific literacy

• An inconvenient truth…

• This chart triggered a great deal of skepticism about climate change…

The Controversy

We need data

• (Note historic record)

The Solution: We have the technology…

• Most important – wean ourselves from coal– Solar power

– Geothermal power

– Wind power

• Cut back on use of fossil fuel for transportation– Fuel efficient vehicles

• Energy efficient appliances

Natural gas is good if there are no leaks in pipelines

No more of these!

The Solution: We have the technology…

• CO2 removal at the source (power plants)

• Pull CO2 out of the atmosphere

– Very costly

• Re-forestation

• Carbon limits and markets

The War on Coal

• Yes, this is one of the most important solutions

• But it is an unfortunate consequence for states that rely heavily on coal for jobs

• As a country we should help those states find other industries to employ people

A Family Values Issue

• The impact will be on our children and grandchildren

• There are many uncertainties, but …

• Do we really want to experiment with our children’s future?

The Importance of

STEM• We all need to be

scientifically literate

• There are numerous policy decisions to be made in the upcoming years with regard to resource management and mitigation of coming changes to our environment

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