What could happen if the climate changes?

Climate change is more than a warming trend (which is why the term “global warming” is an inaccurate description of the phenomenon). Increasing temperatures will lead to changes in many aspects of weather, such as wind patterns, the amount and type of precipitation, and the types and frequency of severe weather events. Such climate change could have far-reaching and/or unpredictable environmental, social and economic consequences.

The global sea level could rise due to several factors including melting ice and glaciers. Rising sea levels could damage coastal regions through flooding and erosion. The climate of various regions could change too quickly for many plant and animal species to adjust. Harsh weather conditions, such as heat waves and droughts, could also happen more often and more severely. Climate change could also affect health and well-being. Many larger cities could experience a significant rise in the number of very hot days. Air pollution problems would increase, placing children, the elderly and people suffering from respiratory problems at greatest risk of health effects. Increases in molds and pollens due to warmer

temperatures could also cause respiratory problems such as asthma for some people.

What are the greenhouse gases?

Water vapour

is the most common greenhouse gas. But others that are very important
too. Some occur naturally and some come from human activity
Carbon Dioxides
or CO2 is the most significant greenhouse gas released by human activities, mostly through the burning of fossil fuels. It is the main contributor to climate

change.

Methane
is produced when vegetation is burned, digested or rotted with no oxygen present. Garbage dumps, rice paddies, and grazing cows and other livestock release lots

of methane

Nitrous oxide
can be found naturally in the environment but human activities are
increasing the amounts. Nitrous oxide is released when chemical fertilizers and manure

are used in agriculture.

Halocarbons
are a family of chemicals that include CFCs (which also damage the ozone
layer), and other human-made chemicals that contain chlorine and fluorine.

What causes climate change?

Earth’s climate changes naturally. Changes in the intensity of sunlight reaching the earth

cause cycles of warming and cooling that have been a regular feature of the Earth's

climatic history. Some of these solar cycles - like the four glacial-interglacial swings

during the past 400,000 years - extend over very long time scales and can have large

amplitudes of 5 to 6°C. For the past 10,000 years, the earth has been in the warm

interglacial phase of such a cycle. Other solar cycles are much shorter, with the shortest

being the 11 year sunspot cycle.

Other natural causes of climate change include variations in ocean currents (which can

alter the distribution of heat and precipitation) and large eruptions of volcanoes (which

can sporadically increase the concentration of atmospheric particles, blocking out more

sunlight).

Still, for thousands of years, the Earth’s atmosphere has changed very little. Temperature

and the balance of heat-trapping greenhouse gases have remained just right for humans, animals and plants to survive. But today we’re having problems keeping this balance.

Because we burn fossil fuels to heat our homes, run our cars, produce electricity, and

manufacture all sorts of products, we’re adding more greenhouse gases to the

atmosphere. By increasing the amount of these gases, we’ve enhanced the warming

capability of the natural greenhouse effect.

It’s the human-induced enhanced greenhouse effect that causes environmental concern,

because it has the potential to warm the planet at a rate that has never been experiencedin human history.

What is the Greenhouse Effect?

A natural system known as the "greenhouse effect" regulates temperature on Earth.

Just as glass in a greenhouse keeps heat in, our atmosphere traps the sun’s heat near

earth’s surface, primarily through heat-trapping properties of certain “greenhouse gases”.

Earth is heated by sunlight. Most of the sun's energy passes through the atmosphere, to

warm the earth's surface, oceans and atmosphere. However, in order to keep the

atmosphere's energy budget in balance, the warmed earth also emits heat energy back

to space as infrared radiation.

As this energy radiates upward, most is absorbed by clouds and molecules of

greenhouse gases in the lower atmosphere. These re-radiate the energy in all directions,

some back towards the surface and some upward, where other molecules higher up can

absorb the energy again. This process of absorption and re-emission is repeated until,

finally, the energy does escape from the atmosphere to space.

However, because much of the energy has been recycled downward, surface

temperatures become much warmer then if the greenhouse gases were absent from the

atmosphere. This natural process is known as the greenhouse effect.

Without greenhouse gases, Earth's average temperature would be -19°C instead of

+14°C,

or 33°C colder.

Over the past 10,000 years, the amount of greenhouse gases in our atmosphere has

been relatively stable. Then a few centuries ago, their concentrations began to increase

due to the increasing demand for energy caused by industrialization and rising

populations, and due to changing land use and human settlement patterns.

Why “global warming” is the wrong term?

Climate change refers to general shifts in climate, including temperature, precipitation,

winds, and other factors. Global warming (as well as global cooling) refers specifically to

any change in the global average surface temperature. Global warming is often

misunderstood to imply that the world will warm uniformly. In fact, an increase in average

global temperature will also cause the circulation of the atmosphere to change, resulting

in some areas of the world warming more, others less. Some areas can even cool.

Unfortunately, although it significantly misrepresents what really happens, the term
‘global warming' is still often used by media and others to describe climate change

What is climate change?

Climate change is a long-term shift in the climate of a specific location, region or planet.

The shift is measured by changes in features associated with average weather, such as

temperature, wind patterns and precipitation. What most people don’t know is that a

change in the variability of climate is also considered climate change, even if average

weather conditions remain the same.

Climate change occurs when the climate of a specific area or planet is altered between

two different periods of time. This usually occurs when something changes the total

amount of the sun's energy absorbed by the earth's atmosphere and surface. It also

happens when something changes the amount of heat energy from the earth's surface

and atmosphere that escapes to space over an extended period of time.

Such changes can involve both changes in average weather conditions and changes in

how much the weather varies around these averages. The changes can be caused by

natural processes like volcanic eruptions, variations in the sun's intensity, or very slow

changes in ocean circulation or land surfaces which occur on time scales of decades,

centuries or longer.

But… humans also cause climates to change by releasing greenhouse gases and

aerosols into the atmosphere, by changing land surfaces, and by depleting the

stratospheric ozone layer. Both natural and human factors that can cause climate

change are called ‘climate forcings', since they push, or ‘force' the climate to shift to new

values.