The Earth
Earth
is the third
planet
from the
Sun
and the only
astronomical
object
known to harbor
life
. While large
volumes of water
can be
found throughout the
Solar System
, only
Earth sustains liquid
surface water
. About 71% of Earth's surface is made up of the
ocean
,
dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of
Earth's surface is
land
, consisting of continents and islands. Earth's
surface layer is formed of several slowly moving
tectonic plates
,
interacting to produce mountain ranges, volcanoes, and
earthquakes. Earth's liquid
outer core
generates the magnetic field
that shapes Earth's
magnetosphere
, deflecting destructive
solar
winds
.
Earth's atmosphere
consists mostly
of
nitrogen
and
oxygen
.
Greenhouse gases
in the atmosphere
like
carbon dioxide
(CO
2
) trap a part of the
energy from the
Sun
close to the surface
Water vapor
,
water vapour
or
aqueous vapor
is the
gaseous
phase
of
water
. It is one
state
of water within the
hydrosphere
.
Water
vapor
can be produced from the
evaporation
or
boiling
of
liquid water or from the
sublimation
of
ice
. Water vapor is
transparent, like most constituents of the atmosphere.
[4]
Under
typical atmospheric conditions, water vapor is continuously
generated by evaporation and removed by
condensation
. It is less
dense than most of the other constituents of
air
and
triggers
convection
currents that can lead to clouds.
Being a component of Earth's hydrosphere and hydrologic cycle, it is
particularly abundant in
Earth's atmosphere
, where it acts as
a
greenhouse gas
and warming feedback, contributing more to total
greenhouse effect than non-condensable gases such as
carbon
dioxide
and
methane
. Use of water vapor, as
steam
, has been
important for cooking, and as a major component in energy
production and transport systems since the
industrial revolution
.
Water vapor is a relatively common atmospheric
constituent, present even in the
solar
atmosphere
as well as every planet in the
Solar
System
and many
astronomical
objects
including
natural satellites
,
comets
and
even large
asteroids
. Likewise the detection
of
extrasolar
water vapor would indicate a
similar distribution in other planetary systems.
Water vapor can also be indirect evidence
supporting the presence of extraterrestrial
liquid water in the case of some planetary mass
objects.
Weather
Climate
Climate
is the long-term
weather
pattern in an area, typically averaged over 30
years.
[1][2]
More rigorously, it is the mean and variability
of
meteorological
variables over a time spanning from months to millions of years.
Some of the
meteorological
variables that are commonly measured
are
temperature
,
humidity
,
atmospheric pressure
,
wind
, and
precipitation
. In a
broader sense, climate is the state of the components of the
climate system
,
including the
atmosphere
,
hydrosphere
,
cryosphere
,
lithosphere
and
biosphere
and
the interactions between them.
[1]
The climate of a location is affected by
its
latitude
/
longitude
,
terrain
,
altitude
,
land use
and nearby
water bodies
and
their currents.
[3]
Climates can be
classified
according to the average and typical variables, most
commonly
temperature
and
precipitation
. The most widely used classification
scheme was the
Köppen climate classification
. The
Thornthwaite system
,
[4]
in use
since 1948, incorporates
evapotranspiration
along with temperature
and
precipitation
information and is used in studying
biological diversity
and
how
climate change
affects it. Finally, the Bergeron and
Spatial Synoptic
Classification systems
focus on the origin of air masses that define the climate of a
region.
Paleoclimatology
is the study of ancient climates.
Paleoclimatologists
seek to
explain climate variations for all parts of the Earth during any
given
geologic
period, beginning with the time of the Earth's
formation.
[5]
Since very few direct observations of climate were available
before the 19th century,
paleoclimates
are inferred from
proxy variables
.
They include non-biotic evidence—such as sediments found in
lake
beds
and
ice cores
—and
biotic
evidence—such as
tree rings
and coral.
Climate
models
are mathematical models of past, present, and future climates.
Climate change may occur over long and short timescales from various
factors. Recent warming is discussed in
global warming
, which results in
redistributions. For example, "a 3 °C [5 °F] change in mean annual
temperature corresponds to a shift in isotherms of approximately 300–
400 km [190–250 mi] in latitude (in the temperate zone) or 500 m [1,600 ft]
in elevation. Therefore, species are expected to move upwards in elevation
or towards the poles in
latitude
in response to shifting climate zones."
[6][7]
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