Transcript File

Re-cap
Greenhouse effect
• Draw a diagram
• What are
GHG’s?
• How does it
cause warming?
• Is it natural?
Greenhouse gases?
The 4 main greenhouse gases are:
•CO2
•Methane
•Methan
•CFCs
•Nitrous Oxide
• Incoming solar radiation passes through the
atmosphere (343 Watts/m²)
• Net incoming solar radiation = 240 Watts/m²
• 103 Watts/m² of radiation is reflected by the
atmosphere and Earth’s surface
• The radiation that reaches the Earth’s surface is
absorbed and the Earth’s surface is warmed. As a
result, the earth emits long wave or infrared
radiation into the atmosphere
• The greenhouse gas molecules trap some of this
infrared radiation and re-emit it back to the earth’s
surface and warms it further. Added greenhouse
gases as a result of anthropogenic activity cause
more infrared radiation to be re-emitted, hence
further warming.
• Some of this infrared radiation is lost into the
atmosphere (240 watts/m²)
What are the greenhouse gases?
Greenhouse gases are made out of:
•water vapour
•carbon dioxide
•methane
•nitrous oxide
•ozone
•chlorofluorocarbons (CFCs)
They are all natural gases, but extra
greenhouses gases can
be made by humans from pollution.
What is global warming?
Global warming is the rise in
temperature of the earth's atmosphere.
It's said that by the time a
baby born today is 80 years old,
the world will be 6 and a half
Global degrees
warmer than it is now.
Warming
Is global warming bad?
The earth is naturally warmed by rays
(or radiation)
from the sun which pass through the
earth's atmosphere
and are reflected back out to space again.
The atmosphere's made up of layers of gases,
some of which are called 'greenhouse gases'.
They're mostly natural and make up a kind of
thermal
blanket over the earth.
This lets some of the rays back out of the
atmosphere,
keeping the earth at the right temperature
for animals, plants and humans to survive
(60°F/16°C).
How do we know the climate has changed?
The worlds climate has been changing over the last 18 000 years,
sometimes getting hotter and sometimes colder as you can see from
the graph below.
Know – what an
invasive species
is
Understand –
the impact
invasive species
have
Skills – explanation,
comprehension,
note taking
A*-A
Analyse
the
evidence
for
climate
change to
assess
how
reliable it
is
B-C
Explain
D
global
warming
Describe
and explain
the
how
evidence
evidence is that can be
used to
collected
as evidence
show
of climate
climate
change
change
How do we know the climate has changed ?
The problem with global warming is
that everyone agrees that it is
happening, but there is fierce
debate about how and why.
Many scientists
believe that
climate change is
a result of the
enhanced
greenhouse effect
How do we know the climate has changed?
• Find out what
evidence there
is to tell us
about past
climates.
• You need to
know how the
method works
and what is
actually tells us
about past
climates
Plenary