The Full Picture

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Instrumental measurements of the upper atmosphere

began in the middle of the 20th century, and satellite

measurements, available in the 1960s, provided even

greater advances in the scientific understanding of the

Earth’s atmosphere and surface. By enhancing coverage

in areas of the world where in situ measurements were

unavailable, satellites have given scientists clearer

insights into the global effects of climate changes.

New capabilities have continued to emerge within the

past one to two decades, as the next generation of satel-

lite instruments provided even greater capabilities to

monitor essential climate variables such as sea level,

ocean colour and wind speed.

The improvements to weather and climate observing

systems which took place during the past several

decades have produced tremendous advances in the

ability to monitor the Earth’s climate, and it is envisioned

that the Global Earth Observation System of Systems

(GEOSS) will provide for even greater advances in the

future. But only through the integration and synthesis of

vast quantities of data (current and historical, instru-

mental and proxy sources, in situ and remotely sensed)

can the observations be used to effectively convey the

changing state of the climate system. This integration

and synthesis enables assessments of how the climate

system is responding to man-made as well as natural

influences.

To fully capitalize on converting the array of Earth

observations into information that provides decision

makers with a reliable source of information on the state

of the climate, a collective approach that relies on coop-

eration and collaboration among nations is essential.

While the capabilities of a single country to monitor and

analyse current and evolving climate conditions with

sufficient historical perspective may be limited, by

working together as a collective body to share data and

technical expertise, the capability to monitor, analyse

and report on the state of the Earth’s climate can be

greatly enhanced.

State of the climate programme

The National Oceanic and Atmospheric Administration

(NOAA) and the World Meteorological Organization

(WMO), along with numerous national and interna-

tional partners, established an annual

State of the Climate

report. The report leverages existing monitoring, analy-

sis and reporting on atmosphere, ocean and land surface

conditions from the global to local scale. By combining

historical data with current observations, the

State of the

Climate

report places today’s climate in a historical

context. It also provides perspectives on the extent to

which the climate system varies and changes, as well as

the effect that climate is having on societies and the envi-

ronment.

More than 150 scientists from over 30 countries are now

part of an annual process to turn raw observations

collected from the global array of observing systems into

usable information. Within the context of centuries of past

climate data, the information enhances the ability of deci-

Future impacts are expected to include diminishing crop produc-

tivity in lower latitudes even for small temperature increases; a likely

increase in the extent of drought-affected areas; reduced water avail-

ability in regions supplied by melt water from major mountain

ranges, and increases in malnutrition as well as vector-borne and

cardio-respiratory diseases.

The magnitude and timing of these and other impacts will depend

in large part on the future rate of warming, as well as other changes

such as the frequency and intensity of extreme weather, climate, and

sea level events. Given the many uncertainties regarding the pace of

future climate change and the areas and sectors throughout the world

that will be most heavily impacted, the need to monitor the Earth’s

climate on an ongoing basis remains one of the highest priorities of

the international community.

Monitoring the Earth’s climate

An understanding of changes in the Earth’s climate is based on

decades and centuries of observations. Included among these are

century-long instrumental measurements of surface temperature and

precipitation, and records of daily data which are useful in under-

standing changes in the frequency and severity of extremes such as

heavy precipitation events, drought and heat waves. When combined

with proxy (paleoclimate) data such as ice cores, tree rings, coral

data and sedimentary records, it has been possible to extend the

study of climate variability and change back thousands and even

hundreds of thousands of years into the past.

Observations are collected from the upper atmosphere to below the

ocean’s surface using a wide array of in situ observing systems, satellites,

and radar. By integrating and synthesizing today’s observations with

historical records from both instrumental and proxy sources, scientists are

able to monitor changes in the Earth’s climate in response to man-made

and natural influences

Photo: NOAA/NESDIS/NCDC

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