ESA_CCI_Intro_lecture_to_climate

Lecture overview
Climate
Climate Change
Essential Climate Variable & Climate change

What is Climate?
Climate is defined as an area's long-term weather patterns. The simplest way to describe climate is to look at average temperature and precipitation over time.

What is Weather?
Weather is the state of the atmosphere at a particular place during a short period of time

Weather vs Climate
Weather
Climate
Can change within a few minutes or hours
Takes very long time to change!

Weather vs Climate
Determined: daily
Looked at by the minutes, hour, day, week
Reported as a forecast
Depends on the weather occurring mainly to the west
Climate helps you determine the weather
Determined: Over time
Looked at by the years
Reported as an average
Depends on the location on Earth
Weather makes up climate
Measures conditions in the atmosphere

Climate variables
Some meteorological variables that are commonly measured are as follows:
Temperature
Humidity
Wind
Atmospheric pressure
Precipitation
Cloudiness

Climate System

What is climate change?
Climate change is a change in the pattern of weather, and related changes in oceans, land surfaces and ice sheets, that have come to define Earth’s local, regional and global climates and occurring over time scales of decades or longer.
Human activities, especially emissions of heat-trapping greenhouse gases from fossil fuel combustion, deforestation, and land-use change, are the primary driver of the climate changes observed in the industrial era.

Climate change causes
Climate Change.
Anthropogenic causes
Natural cause
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Earth
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Global temperature

Natural causes-Internal variability
Illustration by Jayne Doucette, Woods Hole Oceanographic Institution

Natural causes-External forcing
EXTERNAL CLIMATE FORCING
Greenhouse gases
Orbital variations
Solar output
Volcanism
Plate tectonics
Other mechanisms

Natural causes-Orbital variation
Shifts and wobbles in the Earth’s orbit can trigger changes in climate such as the beginning and end of ice ages.
More tilt = warmer summers and colder winters
Less tilt = cooler summers and milder winters
Orbital shifts are so gradual that they can only be observed over thousands of years -not decades or centuries.

Natural causes-solar output
The Sun is the source of energy for the Earth’s climate system.
The Sun’s energy output appears constant from an everyday point of view, small changes over an extended period of time can lead to climate changes.
Source: Swiss National Science Foundation

Natural causes-solar output
A decrease in solar activity was thought to have triggered the Little Ice Age between approximately 1650 and 1850, when Greenland was largely cut off by ice from 1410 to the 1720s and glaciers advanced in the Alps.
Pompenburg with Hofpoort in winter, by Bartholomeus Johannes van Hove (1790-1880)
The Frozen Thames, by Abraham Hondius (c.1625–1691)

Natural causes-volcanism
Volcanic eruption throws out a enormous amount of particles and other gases that effectively shield us from the Sun to lead to a period of global cooling.
Source: https://earthdata.nasa.gov/learn/sensing-our-planet/volcanoes-and-climate-change

Anthropogenic causes
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Greenhouse gases
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Air pollution
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Deforestation
Coal mining
Industrial processes

Greenhouse gases
Greenhouse gases are those that absorb and emit infrared radiation in the wavelength range emitted by Earth.
Solar radiation passes through the clear atmosphere.
Most radiation is absorbed by the Earth surface and warms it.
Some solar radiation is reflected by the Earth and the atmosphere.
Infrared radiation is emitted from the Earth surface.
Some of the infrared radiation passes through the atmosphere and some absorbed and re-emitted in all molecules. The effect of this is to warm the Earth surface and the lower atmosphere.
The burning of fossil fuels like coal, oil, and gas for electricity, heat, and transportation is the primary source of human-generated emissions.

Greenhouse gases
Human enhanced greenhouse gases effect

Greenhouse gases
CO2 concentration in the atmosphere is currently 40% higher than it was when industrialisation began.
Other greenhouse gases are emitted in smaller quantities, but they trap heat far more effectively than CO2, and in some cases are thousands of times stronger.
Source: https://ec.europa.eu/clima/change/causes_en

Greenhouse gases- Carbon Dioxide
Sources: Credit: Luthi, D., et al.. 2008; Etheridge, D.M., et al. 2010; Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.
https://climate.nasa.gov/evidence/

Deforestation
Deforestation is the permanent removal of trees to make room for something besides forest.
This can include clearing the land for agriculture or grazing, or using the timber for fuel, construction or manufacturing.

Air pollution
Air pollution is caused by fertiliser use, livestock production, and certain industrial processes that release fluorinated gases.
Pollutants in the air can produce serious environmental issues and contribute to climate change. The major concerns include:
The ability of pollutants to trap too much heat in the atmosphere
The mixture of gases with moisture in the atmosphere which produces damaging acid rain
The increase in unnatural ozone levels
The presence of particles in the atmosphere that block sunlight

Mining
Coal mining releases methane, a potent greenhouse gas. Methane emissions from coalmines has a global warming potential 21 times greater than that of carbon dioxide over a 100-year timeline (Source IPCC).

Industrial processes
Source: CO2CRC.com
These total emissions for industrial process are comprised of: (Fischedick, Roy et al. 2014)
Direct energy-related CO2 emissions for industry
Indirect CO2 emissions from production of electricity and heat for industry
Process CO2 emissions
Non-CO2 GHG emissions
Direct emissions for waste/wastewater

Consequences of climate change
Photo credit AFP
Photo credit UCSUSA
Photo credit David Paul Morris, Bloomberg
Changes in
Glaciers and ice sheets
Sea level change
Sea ice
Heavy rainfall across the globe
Extreme Drought
Decline in Crop productivity
Changes in ecosystems
Hurricanes
Rise in temperature
Acidification of seawater

Consequences of climate change
Source: ESA

Why measuring Climate Change?
We measure climate change to understand climate, climate variability and climatic changes at the local, national, and regional, and global levels;
To understand better how climate change affects our social systems;
To better plan adaptation measures to tackle the potential or actual impacts of climate change.
Source: U.S. Global Change Research Program

How climate change is measured over time?
Earth-orbiting satellites, remote meteorological stations, and ocean buoys are used to monitor present-day weather and climate.
Paleoclimatology data from natural sources like ice cores, tree rings, corals, and ocean and lake sediments
Scientists use this data as an input into sophisticated climate models that predict future climate trends with impressive accuracy.
Photo credit: Ludovic Brucker
Source: WMO: https://public.wmo.int/en/programmes/global-observing-system

Essential Climate Variables
Essential climate variables (ECVs) are physical, chemical, or biological variables or a group of linked variables that critically contributes to the characterisation of the Earth's climate.
Relevance: The variable is critical for characterising the climate system and its changes.
Feasibility: Observing or deriving the variable on a global scale is technically feasible using proven, scientifically understood methods.
Cost effectiveness: Generating and archiving data on the variable is affordable, mainly relying on coordinated observing systems using proven technology, taking advantage where possible of historical datasets.

Essential Climate Variables
ECV data records are intended to provide reliable, traceable, observation-based evidence for a range of applications, including monitoring, mitigating, adapting to, and attributing climate changes.
ECVs
Land
Ocean
Atmosphere
https://gcos.wmo.int/en/essential-climate-variables

More than a list of variables
Building on existing science, data holdings and observational infrastructure.
ECVs
Reference: Bojinski et al., 2014
Guidance is provided on their observation, and the generation of products from Earth observation.
They provide one basis for an organised assessment of capabilities and needs.
Organisation could be by observing a network, physical/chemical cycle or societal benefit area.

Climate Change Initiative of ESA
The European Space Agency (ESA) has launched the Climate Change Initiative (CCI) to provide satellite-based climate data records (ECVs) that meet the challenging requirements of the climate community.
The aim is to realize the full potential of the long-term Earth observation archives
Aspects of producing a satellite-based climate data records: Data acquisition, Data calibration, Algorithm development, Validation, Maintenance, Provision of the data to the climate research community

What did you learn?
understood the difference between weather and climate
became familiar with concepts of climate change
Read the supporting document What is Climate Change?
became familiar with the climate change causes
became familiar with concepts of ECVs
Read the supporting document Learn more about ECVs