The Sun. Since the sun is the primary driver of climate circulation, even small changes in solar output can be expected to have an effect on global warming and cooling. Some scientists estimate, for example, that from 1645 to 1715 the sun’s output was about 1 percent less than it is today, and this period corresponded to the coldest part of the Little Ice Age. GCM calculations suggest that little of the current warming trend can be attributed to direct solar heating, but cannot rule out more complex interactions. Some scientists suggest, for example, that changes in the sun’s magnetic field may affect Earth’s cloud cover by influencing the cosmic rays whose interactions provide condensation nuclei in the atmosphere.
Ice. The extent and distribution of ice, as well as its movement in glaciers and ice shelves, has an as yet poorly understood effect on climate. For example, ice and snow reflect the sun’s radiant energy back into space, whereas darker rocks and soils more effectively absorb this energy. Might melting ice—for example, in Greenland—accelerate global warming?
Standard practice in the climate change debate is to calculate Earth’s temperature for the case in which atmospheric carbon dioxide doubles. The Intergovernmental Panel on Climate Change (IPCC), which collates the calculations of hundreds of scientists around the world and issues reports every few years, suggested in 2007 that Earth’s average temperature will increase by about 2°C over the next century.
The GCM have not yet progressed to the point where we can make detailed regional predictions about what this sort of warming would entail, but some of the consequences could be coastal flooding, the spread of tropical diseases northward, and major changes in rainfall patterns, which would have profound (and as yet unpredictable) effects on agriculture. In addition, the rapid change in climate can be expected to have a negative impact on many ecosystems and drive many species to extinction.
But how do we reverse the trend? Any effort to reduce drastically the consumption of fossil fuels will cost consumers money and will require significant changes in lifestyle as well. Carbon-based fuels are the energy source for automobiles, jet planes, ships, and most of our electric power plants. Finding ways out of this dilemma is not easy.
A few obvious measures are already being tackled. We can attempt to slow the rapid destruction of rain forests in the Amazon while we are planting new forests elsewhere. Living trees pull carbon out of the air and store it in their tissues, thereby helping to cancel the effect of burning fossil fuels. We can implement new ways to conserve energy while we increase our reliance on such renewable energy sources as wind, solar, and hydroelectric power. We can develop new, more efficient forms of biofuels that balance the carbon dioxide of burning fuel with new plant growth. Efforts in all of these promising areas are being vigorously pursued around the world.
In spite of such promising efforts, the greenhouse effect is the most difficult and alarming of the many environmental problems that face the global ecosystem. On the one hand, it is the most difficult to model because the effects of adding carbon dioxide to the atmosphere are uncertain, while the cost of doing something about it is high. It’s unrealistic to think that you can take the world economy, which runs almost entirely on fossil fuels, and change it over to other sources of energy in a very short period of time. It typically takes thirty to fifty years for a new fuel to work its way into the economy. If the more disastrous predictions of greenhouse warming are true, in about fifty years the warming will already have occurred, and it will be too late to do anything about it.
What’s more, the best scientific estimates suggest that warming will not cause severe environmental changes for several decades, far beyond the planning horizon of corporations, governments, and society’s other major institutions. The question boils down to this: Are you willing to change your lifestyle now because it’s likely that global warming will adversely affect the lifestyles of your grandchildren?
EPILOGUE
The Role of Science
SCIENCE IS A WAY of learning about the cosmos and our place in it. Through science we discover physical laws of governing matter, energy, forces, and motion—universal laws that apply to every life-form and every world, large or small. We explore the atom and the amazing diversity of materials and properties that arises from these building blocks. We identify forces that bind nuclei and fuel stars—forces that can be harnessed for our benefit or unleashed for our destruction.
The scientific method leads inexorably to far-reaching conclusions about planet Earth and our role in its history. Earth is immensely old, formed like all planets and stars from galactic dust and debris. Ours is a dynamic planet with continents and oceans that have been created and consumed a score of times before the present age. Humans are but one small, recent step in the four-billion-year evolution of life on Earth, a process that led from a single living cell to the delightful diversity of organisms we find today. Along the way countless millions of species have come into being, and almost as many have become extinct.
At times we like to think of ourselves as exempt from the laws of nature—as somehow special, protected, and above all other creatures. Yet we cannot alter our place in the cosmos as but one species among millions struggling for energy and nutrients to survive. It would be utter folly to ignore the realities of our place in Earth’s ecosystem.
That being said, it would also be foolish to deny that humans enjoy a special status on Earth. Unlike any other species in the planet’s history, we have learned to harness resources and shape our environment. We possess the ability to probe our world with the sciences, to appreciate our world through the arts, and to search for the meaning of our unique role with philosophy and religion.
Humans are a doggedly curious species, and science provides our most powerful means for understanding the physical universe. Science is a great human adventure, with formidable challenges and priceless rewards, unimagined opportunities and unparalleled responsibilities. Science lets us view the world with new eyes, exploring backward in time, looking outward through space, and discovering unity in the workings of the cosmos. Armed with that knowledge we can combat disease, create new materials, and shape our environment in marvelous ways. Science also gives us the means to predict the consequences of our actions and perhaps, with wisdom, to save us from ourselves.
INDEX
abortion
absolute zero
absorption of light
accelerated expansion
acceleration:
in Newton’s first law
in Newton’s second law
accelerators
acid-base chemical reactions
acid rain
adenine
adenosine triphosphate (ATP)
african plate
agriculture, genetic engineering in
air bags
air quality
algae
alloys
alpha decay
alpha particle
Alps, formation of
alternating current (AC)
aluminum
Amazon, deforestation in
American Association for the Advancement of Science
American Chemical Society
American Geophysical Union
American Institute of Physics
American Physical Society
amino acids
amoeba
ampere (amp)
Ampère, André-Marie
amplitude modulation (AM)
anaerobic bacteria
Andes Mountains
Andromeda galaxy
Andromeda nebula
Antarctic continent
Antarctic ice, melting
antibodies
antigravity
antimatter
apes, and human ancestry
Appalachian Mountains
aquifers
archaea
archean eon
asteroid belt
asteroids
astrology
astronomy
search for Earth-like planets in
solar system
stars
and telescopes
atmospheric cycle
atomic bombs
atomic number
atomic structure
atoms
anatomy of
architecture of
Bohr
chemical bonding of
chemical identity of
heavy
motion of
in quantum mechanics
use of term
visible light emitted by
ATP (adenosine triphosphate)
Australian continent
Australopithecus
Bacillus thuringiensis (Bt)
bacteria:
anaerobic
classification of
barometric pressure
baryonic matter
basalt
B cells
Bell, John
beta decay
beta particle
big bang theory
biochemistry
biofuels
biological evolution
biology
biosphere
biotechnology
bits
black holes
blue-green algae
Bohr, Niels
Bohr atom
bottom and top quarks
Brahe, Tycho
brittleness
brownian motion
butterfly effect
bytes
calculus
calendars
camouflage
cannonballs
carbohydrates
carbon
and life
carbon cycle
and nutrients
carbon dioxide
carbon-14
carbon-14 dating
catalysts
celestial gravity
cell phones
cells
asexual reproduction of
biochemical identity of
as chemical factory
and common ancestor
convection
cycle times of
differentiation
division of
energy for
engulfed
evolution from
first, creation of
functions of
membranes of
nucleus of
specialized
unused
cellulose
celsius scale
cenozoic era
CERN (European Center for Nuclear Research)
chain reactions
chains
chaos theory
chemical bonding
covalent
and electrical conductivity
electrons in
hydrogen
ionic
metallic
and the real world
chemical evolution
chemical potential energy
chemical reactions
chemistry
Chernobyl
Chesapeake Bay
China
China Syndrome
chlorofluorocarbons (CFCs)
chlorophyll
chromium
chromosomes
climate
climate change
clockwork universe
cloning
clouds
coal
cold fusion
color
Colorado Rockies
color spectrum
comets
common ancestor
compasses
complexity theory
composite materials
computers
conduction
conductors
continental drift
continental shelves
continents
convection
Copernicus
copper
core
cosmic rays
cosmological constant
cosmology
cosmos; see also Universe
Coulomb, Charles
Coulomb’s Law
covalent bond
creationism
crossbreeding
crust
cryptography
crystals
curies
cytosine
Dalton, John
dark energy
dark matter
Darwin, Charles
dating, radiometric
decay chains
democritus
deoxyribose
depolymerization
Devils Tower, Wyoming
diabetes
diamonds
digestive system
dinosaurs
diodes
direct current (DC)
DNA
cloning
and common ancestor
double helix of
and evolution
fingerprinting
genetic engineering
“junk,”
molecules of
replication of
stem cells
STRs
VNTR
doldrums
Dolly (cloned sheep)
domains
doping a crystal
Doppler effect
Doppler shift
ductility
E = mc2
Earth
axis of rotation
formation of
as frame of reference
impermanence of
interior of
magnetic field of
oceans of
orbit of
perihelion shift of
and plasma
plate tectonics of
as single integrated whole
Earth cycles
atmospheric
carbon
and climate change
rock
seasons
water
weather
earthquakes
ecological niche
ecology
ecosystems
energy and the food web
human effects on
interconnectedness in
nutrients and the carbon cycle
use of term
Edison, Thomas A.
education
Einstein, Albert:
on Brownian motion
and cosmological constant
and E = mc2
and quantum paradox
and relativity
and thought experiments
unified theory of forces sought by
elasticity
elastic potential energy
Eldredge, Niles
electrical charges
electrical circuits
electrical conductivity
electric current
electricity
Coulomb’s Law
insulators
and magnetism
Maxwell’s equations
motors and generators
semiconductors
static
electromagnetic force
electromagnetic induction
electromagnetic radiation
electromagnetic spectrum
electromagnetic waves
electromagnets
electrons
in electrical charges
interaction of
motion of
orbiting
radio waves from
repulsion of
role in chemistry
electrostatic forces
electroweak force
elements
in combination
periodic table of
superheavy
Ellesmere Island, Canada
embryology
embryonic stem cells
energy
allowed levels of
conduction of
conservation of
and food chain
and heat
interchangeable forms of
kinetic
of light
for living cells
from more useful to less useful
new sources of
nuclear
potential
sun as source of
thermodynamics
types of
use of term
energy waves
engines
entropy
enzymes
ethanol
eucarya
eukaryotes
eurasian plate
Europa
European Food Safety Authority
eve (common ancestor)
evolution
biological
chemical
from common ancestor
creationists vs.
and DNA
evidence for
and extinction
fact vs. theory of
fossil record of
human
intelligent design
molecular
mutations in
natural selection
non-random
rate of
story of
and survival
theory of
extinction
mass
Fahrenheit, Daniel
Fahrenheit scale
fault zones
Federal Communicaitions Commission
fermentation
Fermilab (Fermi National Accelator Laboratory)
fertilization
Feynman, Richard
Feynman diagram
fiber composites
fission
flagellum
flu
fluorescent materials
food:
from cloned animals
genetically engineered
Food and Drug Administration, U.S.
food chain:
energy in
radioactive tracers in
trophic levels of
force:
attractive
in Newton’s laws of motion
repulsive
and work
forces
electromagnetic
electrostatic
electroweak
gravity
strong
unified field theories
weak
fossil fuels
“fossil” genes
fossil record
frames of reference
freezings
frequency:
measurement of
range of
use of term
frequency modulation (FM)
freshwater
Freud, Sigmund
friction
Science Matters Page 31