The Truth About
Global
Warming
The Earth
and the Arguments are Heating Up!
This
is all about…
•
Heat and Light
•
Gases in the
atmosphere and how they influence the heat balance of the Earth
•
How oceans affect
global climate change
•
Cause and effect
•
Climate change in
the last 2 million years
• Are
human activities causing global warming significantly to cause catastrophic
environmental harm to the Earth?
• The
mechanism for global warming has been blamed on the “Greenhouse Effect.”
• In
a greenhouse, shorter wavelengths of light energy come through the glass. The
rays hit the potted plants and other heat absorbing surfaces. The heated
surfaces in the greenhouse reflect longer-wave radiation back towards the
glass. The rays hit the glass and are
reflected back and are trapped.
The greenhouse heats up. Visible
light (except for green light) provides the plants with energy to undergo
photosynthesis—where, during the day, they make carbohydrates and oxygen out of
water and carbon dioxide. The heat keeps the plants in their proper temperature
range.
•
On a sunny, cold
winter day, the greenhouse (or a glassed-in porch) can be warm and
pleasant. On a sunny, hot summer day,
the greenhouse can be an inferno if it is not sufficiently ventilated. Although some of the internal heat is
conducted through the glass and escapes the greenhouse, the greenhouse can heat
up too much and kill the plants without proper ventilation. Is the atmosphere overheating?
•
Gases in the
atmosphere can act like the glass in a greenhouse.
– Solar radiation hits the Earth. Incoming radiation hits the gases of the
atmosphere. The radiation can be
reflected directly back into space, absorbed by the gases in the atmosphere, or
reach the Earth’s surface (50%).
– Shorter wavelengths can penetrate better than longer
wavelengths, except through ozone where some of the ultraviolet is
absorbed. But that’s another story.
– The Earth’s surface heats up, and reradiates excess
infrared heat upwards. But the greenhouse gases act like a trap to absorb and
re-reflect outgoing radiation back down to Earth.
The
Earth would be a frozen planet without the benefit of the greenhouse
gases. These gases include:
CO2
– carbon dioxide
CFCs--
chlorofluorocarbons
CH4-- methane
O3-- ozone
H2O–
water (vapor)
Instead
of an average daily temperature on Earth of -17oC (1.4oF),
we maintain an average daily temperature on Earth of +14oC (57.2oF).
Carbon
Dioxide
Carbon dioxide is produced by natural and
industrial combustion in the presence of sufficient oxygen. It is the gas we and other life forms exhale
and the gas that is needed by plants to perform photosynthesis. This gas is
industrially produced by burning fossil fuels, for transportation, for heating,
and for manufacturing. It is also
produced naturally from organic decay, forest fires, volcanoes, and by rock
weathering.
Chlorofluorocarbons
CFCs are not naturally produced. They have been manufactured for use in
refrigeration, degreasing, insulation, foams, and propellants in aerosol cans.
CFCs have been phased out by international protocol.
Methane
Methane is produced from natural and industrial sources -- from natural
seepage of fossil fuels, combustion, landfills, plant decay in natural
wetlands, wetland agriculture, livestock and termites.
Ozone
and NOx
Ozone and NOx are produced (at ground level) from combustion
(transportation and industry) – they are respiratory irritants. Stratospheric
ozone is produced by lightning and helps to absorb ultraviolet rays. NOx is
also produced from fertilizer manufacture and natural plant decay.
Water
Vapor
Water vapor can also act as a greenhouse gas. Water is part of the hydrologic cycle. It
collects in the atmosphere as a vapor through evaporation, absorbs incoming
radiation, reacts with other gases, and affects the weather and climate. When it precipitates, it can remove
particulates from the air and wash them into the oceans or deposit them on
land.
•
Volcanic
eruptions increase the atmospheric concentration of many greenhouse gases. However, volcanoes also release particulates
into the atmosphere which help to reduce the total amount of solar energy that
reaches the Earth’s surface.
It is undeniable, that we are pumping significant amounts of carbon dioxide
into the atmosphere,
and at the same time removing forests, whose plants, could absorb the
carbon dioxide by day.
Plants
need oxygen too!
•
It is also true
that plants use oxygen and release carbon dioxide at night, when photosynthesis
is not possible. After plants die,
decomposers use oxygen and give off carbon dioxide as the plant tissues decay.
It is also true that more oxygen is being
produced by one-celled plants floating in the world’s oceans than by
terrestrial plants. Furthermore, carbon
dioxide is absorbed by plankton and bi-valve mollusks in producing calcium
carbonate shells. Also, carbon dioxide is used by corals, with the help of
algae, to produce limestone reefs that rim the continents on continental
shelves.
Construction
projects absorb CO2
Carbon dioxide is also absorbed during the curing process of concrete.
Biosphere 2 found this out the hard way.
This doesn’t mean we need to pave the Earth in order to keep CO2
levels low.
Oceans
affect global climates
•
In addition to
atmospheric controls of global climate, we must also factor in the effect of ocean
circulation. Atmospheric circulation is
tied to ocean circulation. The oceans
and lakes control the El Nino effects, the Gulf Stream and other shallow and
deep-ocean currents, lake-effect snows, the availability of water vapor from
sea-water evaporation, the distribution of global heat through deep ocean
currents, and the presence of ice covered seas and lakes.
What’s
the forecast?
• Are
there too many variables for predicting global-climate change? Indeed, we cannot forecast the weather more
than one or two days in advance (at best), and then we are right about 80
percent of the time. For weekly and
seasonal forecasts, the TV weather forecasters, who must come up with a
prediction day after day, are no better than the Farmer’s Almanac, the paths of
furry caterpillars, or the groundhog’s shadow.
Can
we predict the future?
• If
we try to predict the climate in the next 20 years, with all the sophistication
of computer simulations (including uncertain assumptions), we are playing the
climate lottery. Yes, if you play the
climate lottery-- Odds are you will not have fun.
• Can
we use the past to predict the future? Ask your stock broker.
Cause
and Effect
•
In Sweden, the
stork population has increased and so has the human population. Therefore, babies come from storks.
Cause
and Effect
•
On Earth, average
annual temperature has increased and so has the concentration of carbon
dioxide. Therefore, carbon dioxide
causes global warming?
Do
increases in greenhouse gases cause global warming?
• Just
because greenhouse gases are increasing and world temperatures are increasing,
this doesn’t mean that one causes the other.
Is
the cart pulling the horse?
• Maybe
it’s the opposite: “Global warming causes increases in greenhouse gases.” Increased temperatures can cause the
greenhouse gases to increase through greater oxidation (more CO2 and
NOx), more forest fires (more CO2 and NOx),
more vegetation decay (more methane and NOx), more evaporation and
cloud formation (more H2O vapor in the atmosphere).
Maybe
they are independent variables?
Global Warming?
Is
the Earth warming up? Yes!
Why?
But what happened before the industrial revolution and even
before the dawn of civilization?
•
The Earth has
experienced four major and several minor glaciations in the last 2 million years.
•
Between
glaciations, we have had periods of global warming greater than what we see
today.
•
During the last
major glaciation, ice covered two-thirds of Ohio as late as 30,000 years ago
and had not completely melted away until about 10,000 years ago.
What is a glaciation? A small decrease in temperature can cause
snow to last through summers, especially at high elevations and latitudes. Successive accumulations of snow over many
thousands of years cause glaciers to grow.
Glacial
Map of the Midwest
Remnants
of the Last Ice Age
• The
Kent Bog, south of Kent, Ohio, still clings to its boreal vegetation, with
tamarack trees (deciduous conifers) and sphagnum moss exactly what is currently
present in northern Minnesota and Canada.
Kent
Bog
• From
1500 A.D. to 1750 A.D., Europe noted an advance of glaciers in the Alps known
as the Little Ice Age.
We are coming out of the last Ice Age
• Prior
to the Little Ice Age, the Vikings were able to colonize Greenland, Iceland,
and parts of maritime Canada. They
called one of their lands of colonization “Greenland,” as it wasn’t as
ice-covered as it is now.
In other words, are we looking at a rise
as part of a larger fall?
We are coming out of an ice age. Shouldn’t we expect natural global warming?
The cyclic fluctuation of climate can be as difficult or more difficult to predict as the Dow Jones Average.
• So
if the increase in greenhouse gases in the atmosphere is not causing the
apparent warming of the planet, then what is?
Why are we coming out of a glaciation and what caused the last
glaciation, and the cyclic glacial/interglacial alternation in the last
two-million years?
• Causes
of glaciations have been discussed by geologists for many years. Geologists
have proposed multiple working hypotheses for the natural causes of
glaciation—natural, because glaciation existed before human civilization.
• The
following variables are known:
– Output
of solar radiation from our Sun is variable and cyclic. Solar storms and flares are harbingers of
climatic change.
– The
Earth wobbles on its axis, causing changes in the angles that solar radiation
hits the Earth. As with seasonal
changes, the angle of solar rays affects the heating and cooling of the Earth.
– Glaciation produces reflectors in the form of ice and
snow cover. The entrapment of the
earth’s water budget in ice and snow reduces the amount of water necessary for
evaporation and precipitation which reduces snowfall and the formation or
maintenance of glaciers. With decreased
snow and glaciers, more of the surface can absorb more incoming radiation and
the Earth heats up. This cycle repeats
itself every several 100,000 years.
– More precipitation dissolves more minerals on the land
and increases the salinity of the seas.
Saline water is more dense and causes major warm-water currents to go
deep and not warm the continents (e.g., Gulf Stream warming Europe). After the liquid water budget lessens, less
input of minerals occurs and the warm-water currents surface and warm the
continents. This cycle repeats.
•
Should we
reduce our greenhouse gas emissions? If
this does cause an effect on the cyclicity of global warming/cooling, could we
be in danger of plunging the Earth into another ice age prematurely?
Reduction of fossil fuel combustion emission may be a good idea to
promote good air quality. But, will it
prevent an environmental disaster from global warming or cause another
environmental disaster from global cooling.
We need a lot more research.
Global
Warming was caused by:
– Human
input to greenhouse gases
• Solution:
reduce emissions until a change is noticed or adapt to changing conditions
– Natural
input to greenhouse gases
• Solution:
adapt to changing conditions
– Natural
temperature increases independent of input to greenhouse gases (causes of
glaciation)
• Solution:
adapt to changing conditions
– All
of the above
• Next
slide….