2 Truths and a Lie:
Directions
Take a set of “2 Truths and a Lie”
cards. Place the pile on your desk
between you and a partner or
group. One person reads the card
aloud. Discuss which answer (A,B,
or C) you feel is not true - the
LIE. There is only one lie per
card. Each person should explain
their reasoning to the others.
When you have each given your
ideas, turn the card over and find
out the real lie. Discuss! Put this
card in a separate “discard” pile
and move on to the next.
2 Truths and a Lie:
Extreme Weather
2 Truths and a Lie:
Future Temps
A. Doubling atmospheric CO2
would lead to a 1°C bump in
Earth’s average temperature.
B. Melting polar ice will slow
down warming trends because
heat is absorbed in the
process.
C. Temperature and CO2 levels
are proven to be related, so
the increasing levels of CO2
currently being observed will
lead to more warming.
2 Truths and a Lie:
Oceans
A. Heavy downpours and flooding
events are increasing in some
areas.
A. Oceans contribute to
atmospheric carbon dioxide
levels by emitting CO2.
B. Extreme weather proves the
existence of global warming.
B. Oceans have been getting
more acidic due to warmer
global temperatures.
C. Warmer temperatures amplify
the impacts of droughts
because increased temps
enhance evaporation from soils,
making droughts worse than
they would be under cooler
conditions.
C. The temperature of the
upper layer of the ocean has
increased by about 0.13°C per
decade over the last 100
years.
©Flying Colors Science
2 Truths and a Lie:
2 Truths and a Lie:
Answer B is a LIE. Temperature
and CO2 levels are related, so the
increasing levels of CO2 being
observed will lead to more
warming. Doubling atmospheric
CO2 would lead to a 1°C bump in
the Earth’s average temperature.
However, there’s a catch. If
temperatures increased that
much, ice would melt much more,
and ice reflects the sun’s heat.
More heat would be absorbed,
causing an even bigger increase in
global temps – an estimated 3°C
versus 1°C.
Take a set of “2 Truths and a Lie”
cards. Place the pile on your desk
between you and a partner or
group. One person reads the card
aloud. Discuss which answer (A,B,
or C) you feel is not true - the
LIE. There is only one lie per
card. Each person should explain
their reasoning to the others.
When you have each given your
ideas, turn the card over and find
out the real lie. Discuss! Put this
card in a separate “discard” pile
and move on to the next.
Future Temps
2 Truths and a Lie:
Oceans
Answer B is a LIE. The oceans
have been getting more acidic – a
huge concern for marine life,
especially animals with shells and
coral. However this change is not
due to temperature but rather to
the ocean absorbing more CO2.
(Human activity has made
atmospheric levels higher.) This
causes carbonic acid to form. The
oceans do contribute to
atmospheric carbon dioxide,
however this is a natural process
that previously was a part of a
balanced carbon cycle.
Directions
2 Truths and a Lie:
Extreme Weather
Answer B is a LIE. Extreme
weather itself does not prove the
existence of global warming, but
is evidence it is occurring.
Warming will exaggerate extreme
weather by altering ocean
currents, providing extra heat to
form tornadoes and hurricanes,
and causing more precipitation.
Heavy downpours and flooding
increase because warm air can
hold more water vapor than cooler
air. Warmer temps amplify
droughts because they increase
evaporation from soils.
©Flying Colors Science
2 Truths and a Lie:
Historical Temps
2 Truths and a Lie:
Carbon Dioxide
A. Ice core data shows that
Earth’s climate has always
changed.
A. The concentration of carbon
dioxide in Earth’s atmosphere
is at a record-breaking level.
B. Earth has experienced
warmer periods in the past.
B. For the very first time in
history, carbon dioxide levels
have exceeded 400 parts per
million.
C. Earth’s temperatures have
never been as high as they are
today.
2 Truths and a Lie:
Deforestation
A. Clearcutting trees is
considered deforestation.
B. Trees and plants remove
carbon dioxide from the
atmosphere.
C. Deforestation in places like the
Amazon jungle is contributing
to increased levels of carbon
dioxide in the atmosphere.
C. Carbon dioxide is a pollutant
in the atmosphere.
2 Truths and a Lie:
Food Chains
A. Human food sources will be
impacted by climate change
even though much is grown on
farms.
B. Changes in arctic sea ice is
leading to less ice algae – an
important base of the arctic
food chain.
C. Organisms at the top of the
food chain (humans, hawks)
will be at the least risk when
food chains are disrupted.
©Flying Colors Science
2 Truths and a Lie:
Carbon Dioxide
Answer C is a LIE. The
concentration of CO2
in Earth’s atmosphere is at a
record-breaking level. Levels of
CO2 have changed throughout
Earth’s history, reaching a max of
about 300 ppm. Never in Earth’s
history has it gotten to the level
it is today – over 400 ppm.
Although CO2 is not a pollutant –
it is a very natural part of the
atmosphere and carbon cycle –
this current level is not due to
natural processes and has been
caused by human activities.
2 Truths and a Lie:
Historical Temps
Answer C is a LIE. Ice core
data shows that Earth’s climate
has always changed. Earth had
warmer periods in the past,
like in the Neoproterozoic period
(600 - 800 mya) and the
Paleocene-Eocene Thermal
Maximum (56 mya). However,
Earth’s temps are warming
fast – faster than at the end
of an ice age. In the 2000’s
some places experienced twice
as many record high
temperatures than low.
2 Truths and a Lie:
2 Truths and a Lie:
Answer C is a LIE. Food will be
impacted even though much is
farm grown. Droughts may
decrease available water for crops
and changing rain patterns may
alter planting/harvest patterns.
In natural food chains, there are
already effects. Changes in sea
ice is leading to less ice algae – a
base of the arctic food chain.
Organisms at the top of food
chains, large consumers, are at the
most risk when food chains are
disrupted because as a group they
have the least energy available to
them in the first place.
Answer A is a LIE. While
clearcutting trees decreases the
number of trees that remove CO2
from the air, it isn’t considered
deforestation. Deforestation is
when the way the land is used
changes, for example when jungle
is turned into livestock feed lots.
This is contributing to increased
levels of carbon dioxide in the air
because there is less carbon
dioxide being removed by plants
through photosynthesis. Up to
13% of global carbon emissions
come from deforestation.
Food Chains
Deforestation
©Flying Colors Science
2 Truths and a Lie:
Polar Bears
A. Loss of sea ice makes it
difficult for polar bears to
hunt for seals.
B. Polar bears are an endangered
species.
C. Some populations of polar
bears are actually increasing.
2 Truths and a Lie:
Measuring Change
A. Scientists can study Earth’s
climate up to almost a million
years ago – before people even
existed.
B. NASA uses space satellite data
to study climate issues and sea
ice on the surface of Earth.
C. Scientists collect temperature
data from 15 land-based data
stations around the world.
2 Truths and a Lie:
Sea Ice
A. How far sea ice extends (its
range) is more important to
climatologists than its volume.
B. In 2018, NASA reported that
wintertime ice has been
growing, slowing down a more
long-term decline.
C. NASA says that since 1958
the arctic sea ice has lost on
average around two-thirds of
its thickness.
2 Truths and a Lie:
Greenhouse Gases
A. Naturally occurring water
vapor is a greenhouse gas,
and there is more of it in the
atmosphere than CO2.
B. Greenhouse gases are
dangerous and must be
reduced by at least twothirds to halt global warming.
C. CFCs are man-made gases
used in aerosol cans,
refrigeration and A/C that
trap heat in the atmosphere.
©Flying Colors Science
2 Truths and a Lie:
2 Truths and a Lie:
Answer A is a LIE. Scientists
don’t worry as much about how
much “sea ice extent” changes,
because it is affected by wind
and ocean currents, not just
temps. They’re very concerned
with how much ice volume has
been lost. NASA says that since
1958 the arctic sea ice lost on
average around 2/3 its thickness
and 3,100 cubic kilometers of
volume per decade. However, in
2018, NASA reported that
wintertime ice has been growing,
slowing a more long-term decline.
Answer B is a LIE. There are
several separate populations of
polar bears in the arctic. Some of
these populations are actually
increasing, while others remain
constant or are decreasing. Polar
bears are not on the endangered
species list. They are listed as
“vulnerable” by the IUCN, the
International Union for
Conservation of Nature.
Decreasing sea ice could affect
polar bears in the future because
they do use sea ice as a platform
to hunt for seals.
2 Truths and a Lie:
2 Truths and a Lie:
Sea Ice
Greenhouse Gases
Answer B is a LIE. There are
naturally occurring greenhouse
gases, including water vapor
(3%), CO2 (0.04%), and methane.
At normal levels they are
necessary for life because they
trap heat and keep Earth the
perfect temperature for living
things. Reducing their levels a
lot would make Earth too cold.
But, human activities have
added extra CO2, methane and
man-made CFCs so more heat is
trapped and the greenhouse
effect is exaggerated.
Polar Bears
Measuring Change
Answer C is a LIE. The U.S. Air
Force Climatology Center has over
9,000 worldwide stations
collecting data every day. Other
climate organizations have
thousands more locations
collecting data. Scientists also
study Earth’s climate and carbon
dioxide levels up to almost a
million years ago by obtaining ice
cores. NASA uses space satellite
data to study climate issues on
the surface of Earth, especially
sea ice data.
©Flying Colors Science
2 Truths and a Lie:
Sea Levels
A. Sea levels have been rising at
unprecedented rates, up to an
inch per year.
B. Sea levels increase when the
planet warms because water
expands when it is heated,
making it take up more space.
C. Sea levels rise because polar
ice is melting, leading to more
water in the oceans.
2 Truths and a Lie:
Fossil Fuels
A. The biggest reason people burn
fossil fuels is for cars and
other types of transportation.
B. Fossil fuels are natural, and
were formed by the process of
decaying ancient plants and
animals.
C. Burning fossil fuels releases
carbon dioxide into the
atmosphere that would
otherwise have been trapped
underground.
2 Truths and a Lie:
Natural Causes
of Warming
A. Changes in the brightness of
the sun and solar activity
could account for climate
change.
B. Volcanoes emit 200 million
tons of carbon dioxide each
year.
C. Natural land and ocean
processes emit 780 gigatons
of carbon dioxide per year.
2 Truths and a Lie:
Emissions
A. Emissions of methane are
much lower than CO2
emissions, but methane is a
much more powerful heat
absorber than CO2.
B. Humans have released 2000
gigatons of extra CO2 into
the atmosphere since 1870.
C. Carbon dioxide levels in the
atmosphere are up a solid
10% since the Industrial
Revolution.
©Flying Colors Science
2 Truths and a Lie:
Natural Causes
of Warming
Answer A is a LIE. Changes in
solar activity could not account
for climate change because as
Earth has gotten warmer since
1950, solar activity has decreased.
Volcanoes and natural land and
ocean processes do emit carbon
dioxide, but these emissions were
previously balanced in the carbon
cycle. Now, humans are adding an
extra 35 gigatons of CO2 to the
atmosphere, leading to warming.
2 Truths and a Lie:
Sea Levels
Answer A is a LIE. Sea levels
have been rising at alarming
rates, about one tenth of an inch
per year, or an inch a decade,
over the last 100 years. This is
caused two ways: sea levels
increase when the planet warms
because water expands when it is
heated, making it take up more
space, and because polar ice is
melting, leading to more water in
the oceans.
2 Truths and a Lie:
2 Truths and a Lie:
Answer C is a LIE. CO2 levels
are up 40% since the Industrial
Revolution! In fact, humans have
released 2000 extra gigatons of
CO2 into the air since 1870.
Methane emissions, another
greenhouse gas, are much lower
than CO2 levels, but even at
lower levels do have an effect on
climate because methane is a
more powerful heat absorber
than CO2. However, because the
levels are so much higher, CO2 is
the most important gas when it
comes to warming.
Answer A is a LIE. The biggest
reason people burn fossil fuels is
for electricity production, but
transportation is in pretty close
second place. Combined, they
account for about 60% of carbon
emissions. Although fossil fuels
are natural, burning them
releases carbon dioxide into the
atmosphere that would otherwise
have been trapped underground.
This adds more carbon dioxide
to the carbon cycle than would
occur naturally without people
burning fossil fuels.
Emissions
Fossil Fuels
©Flying Colors Science