Download
1 / 59
590 likes | 717 Views
OUR CLIMATE IS CHANGING!. OUR CLIMATE HAS ALWAYS BEEN CHANGING!. Lars Hagen Aug 2007. lbhagen@roanokeslant.org. http://www.roanokeslant.org/GlobalWarmingThoughts. Forward: Page Down Back: Page Up. This Power Point Presentation Encourages
E N D
OUR CLIMATE IS CHANGING! OUR CLIMATE HAS ALWAYS BEEN CHANGING! Lars Hagen Aug 2007 lbhagen@roanokeslant.org http://www.roanokeslant.org/GlobalWarmingThoughts Forward: Page Down Back: Page Up
This Power Point Presentation Encourages Critical Thinking about the Causes and Magnitude of Global Warming and Climate Change Key Components of Critical Thinking are based on Comparisons and Conflicts and Trade-offs Single Thoughts and Views Discourage Critical Thinking and Intellectual Development and are Contrary to Creative Thought and Discussion Lars Hagen www.roanokeslant.org/GlobalWarmingThoughts
Let’s think about Global Warming with an open mind! The key item of discussion is the cause and effect of global temperature • Cause and effect relationships can be difficult to determine and even more difficult to prove • Everyone does not share the same views and opinions and conclusions about the cause & effects of Global Warming • That’s an OK thing! • Let us celebrate diversity of thought and opinion!
Determining Cause & Effect is sometimes illusive As a youngster growing up in maple tree country I was told that the maple leaves turned from green to red in the fall because of the frost. Seemed logical to me! Later I learned that the change is caused by the SUN! Shorter days effects the photosynthesis within the leaves, there is reduced GREEN-chlorophyll, the leaf dies and the remaining glucose is RED (who could have seen that coming?)
Weather is weeks, climate is years • Climate is a long term view of weather • The climate of the world has always been changing and continues to change • Cycling from cold to hot and back again
The earth has had cold climates • 16,000 years ago so much water was frozen into glaciers that the Atlantic Ocean was 400 feet lower than it is today.
What ocean view? • The US east coast extended out approximately 50 miles to where the Hudson River dropped off the continental shelf into the Atlantic Ocean
Where did all the beaches go? • Long Island NY was not an island • The Chesapeake Bay was not a Bay • The Outer Banks were 50 miles from the ocean Apparently there Has been a lot Of warming and Melting long before man made campfires!
Warm can be good! But not too warm! • Approximately 1,000 years ago there was a warm period that was called the Medieval Warm Period • During that time Europe was warm enough for grape vineyards to grow in London.
Cold can be good! But not too cold! • From 1400 to 1750 there was a cold period called the “little ice age”. • During that time Europe was much colder than now and the Thames River in London froze solid most winters.
Making a glacier is a big cold job During that time many glaciers were formed, including the Mendenhall Glacier in Juneau Alaska. The end of the “little ice age” was followed by a warming period that continues today.
How big is our warming? • Many people think that the earth is getting warmer faster than they expected it to. • There is NASA information that indicates that the average temperature of the US has increased approximately one degree in the past 100 years • There is NASA information that indicates that the average temperature of the world has increased approximately one degree in the past 100 years
Isn’t 1/10th of one degree (0.1) small? The climate scientists are publishing global temperatures to a precision of 1/10th of one degree! Can you measure and then calculate the average temperature inside your home for today (24 hours) accurate to within 1/10th of one degree? Can you record your own average body temperature for today (24 hours) within 1/10th of one degree? How do they do that? Is precision = accuracy?
Our body temperature varies 2 deg. daily A temperature of 98.6 is precise – but does it accurately reflect our daily temperature? • - What is the daily average temperature for this example? 100 97
Let’s hear it for the atmosphere! • The earth gets most of its heat from the sun. If there were no atmosphere on earth it would be very hot during the day when the sun is shining on the earth
Not much growing on the moon! • It would be very cold at night as the earth radiated heat back out into space. • That is the situation on the moon.
There’s a diversity of stuff in the 1% • The atmosphere serves a very important role of controlling earth’s temperature and therefore our climate. • Our atmosphere is composed of approximately 21% oxygen and 79% nitrogen and less than 1% of other gases. • These other gases include water vapor, CO2, methane, argon, helium, ozone and others
How can we make more clouds? • Water vapor plays a major role in how much heat reaches the earth and how much heat leaves the earth. • Water vapor as clouds acts as a large shade keeping much of the suns heat from reaching the ground during the day. • Clouds block the earth’s radiation into space at night, helping to hold the heat in the earth.
Who invented the earth’s “greenhouse”? • This action by water vapor and other “greenhouse” gases in the atmosphere is called the “greenhouse” effect. • A greenhouse is intended to moderate and control temperature and humidity to allow plants to grow that otherwise could not survive the high and low temperatures outside the greenhouse.
Greenhouses are Cool! (In the summer) Greenhouses are Hot! (In the winter) They let the desired heat/light in They keep the desired heat in We can control temperature in a greenhouse! But, we have never before controlled the weather or the climate!
Carbon Dioxide is everywhereWe generate it with every breath we takeMethane uses the other exit • Carbon Dioxide (CO2) is a component of greenhouse gas. • CO2 is a naturally occurring gas associated with all living things. • There are also large amounts of CO2 in the ground and in the oceans. • CO2 is also man-made. It is part of the result of burning fuels that contain carbon. • Carbon based fuels include wood, coal, oil and gas (things that once were alive)
Is too much of a good thing a good thing or a bad thing? • There are people who believe that CO2 in the atmosphere is now playing a major role in increased temperature of the earth. • They further believe that man-made CO2 is causing a major increase in temperature and that this will greatly increase as man-made CO2 increases. • Currently man-made CO2 is less than 5% of the total CO2 in the atmosphere • Total atmospheric CO2 contributes less than 5% of the total greenhouse effect. • Water vapor accounts for 95% of the total greenhouse effect!
Is CO2 making things hot or not? • There is data from ice-core samples that supports the view that historically earth’s temperatures are high when CO2 levels in the atmosphere are high. • They further believe that significant amounts of additional man-made CO2 will cause major increases in temperature. • And that will result in making major bad things happen to ocean levels and food supplies and diseases.
Temperature & CO2 There have been many big hot/cold cycles in earth’s history long before man-made CO2. Note the historic temperature and CO2 changes (Does this infer a cause/effect relationship?) The very large time scale makes it difficult to accurately compare the details of the two curves
Note that the Temperature (red) starts falling while the CO2 is still rising. It’s 800 hundreds years after the temperature starts falling before the CO2 starts falling Isn’t that inconsistent with increasing CO2 causing increasing temperature? Which one is the real cause & which is the effect?
“Man-made CO2 is Bad”it’s a best seller but, is it fact or is it fiction or, somewhere in between • The people who believe that man-made CO2 is a big problem are getting and have gotten major media attention and coverage. • These people include scientists belonging to a UN climate committee and individuals like Mr. Al Gore who wrote a book called “An Inconvenient Truth” and a Power Point Presentation that has received wide distribution and public exposure.
How can CO2 be the cause now when it never was before! Or, was it? • There are people who believe that the earth is in a 250 year warming cycle that started at the end of the “little ice age” (approx 1750) • They believe that this warming was well underway before there was any significant man-made CO2 and that this warming cycle is part of the earth’s natural cycles. • They believe that CO2 is not the “major causal factor” in greenhouse gases
Can CO2 go somewhere and then come back? • Because historically temperature dropped hundreds of years before the CO2 dropped it appears that changes in temperature may actually be causing changes in atmospheric CO2 not the other way around • CO2 is a gas that disperses into the air • Rising temperature can cause CO2 to move from within the oceans into the atmosphere! • Falling temperature can cause CO2 to move from the atmosphere into the oceans.
_ Test this concept: shake and then open a bottle of warm soda
Why did the glaciers start melting before there was man-made CO2? There was very little man-made CO2 before World War 1 (1918) However, current Glaciers started melting when the “little ice age” ended in 1750 If man-made CO2 didn’t cause these glaciers to melt – what did? For sure it was something, and it wasn’t us!
Why did the Mendenhall Glacier retreat? Note the amount of glacier retreat (melting) before There is significant CO2 from the Industrial Revolution
Do changes in solar energy matter? • There are people who believe that the sun sends energy into space that is not constant or uniform and that this solar energy has a major effect on cloud formation and therefore a major effect on the earths “greenhouse”. • There were very few “sun spots” during the little ice age when our climate was cold. • There have been significant “sun spots” during times of climate warming • There have been significant “sun spots” during the past 30 years
The study of global warming and Glacier melting is not new, it has been going on for a very long time Galileo studied and documented solar activity with his telescopes starting in 1612 This paper by D.B. Lawrence, 1950) includes an analysis of Mendenhall Glacier, its retreat, and relationship to Solar Activity
