2.0 - Carbon Efficiency¶

2.1 - Introduction¶

Understanding the environmental impact of greenhouse gases is key to understanding software's carbon footprint.
One should consider:
The kinds of greenhouse gases that exist
How the gases in the environment are emitted and measured.
Who is attempting to control and reduce these emissions; and how.
The GHG Protocol.

Global Warming: The long-term heating of earth's climate system, observed since the pre-industrial period.
Effect occuring due to human activities, mainly fossil fuel burning.
Climate Change: Long-term shifts in temperatures and weather patterns. Some shifts are natural, but human activities are often the driver.

Weather: The conditions of the atmosphere over a short period of time
Climate: The conditions of the atmosphere over long periods of time
Any changes to long-term conditions result in short-term changes.
Example: If the average atmosphere temperature increases, the average temperature of the weather will also increase.
Examples of measurable changes to weather conditions due to climate change include:
Changes to water cycles and rainfall
Icecaps melting
Land, air and ocean heating
Ocean currents, acidity and salinity changes.
A lot of the changes can lead to flooding in coastal and rural areas; the latter via increased rainfall. Drought, wildfires and more frequent extreme conditions may also occur.

Greenhouse gases: A group of gases that trap heat from solar radition in the Earth's atmosphere.
The gases act as a blanket, increasing earth's surface temperature.
This is a natural phenomenon that is being accelerated due to carbon emissions, the acceleration is now at a afaster rate than animals and plants can adapt to.
The grenhouse gases and effect are essential for life on earth, and typically comes from natural sources such as animals and geological activity.
The effect allows earth to have a higher temperature than it would via solar radiation alone, but it must be managed appropriately.

Carbon acts as a broad term to cover the impact of all types of emissions and activities relating to global warming.
CO2eq/CO2-eq/CO2e = Carbon equivalence - the term used to measure impact.
Example: 1 ton of methane = 84 tons of CO2 over 20 years, it is therefore 84 tons CO2eq.

To try and mitigate the effects of climate change, some agreements and events have been arranged, a summary follows:

An international treaty agreed in 2015 by 196 parties and the UN to reduce earth's temperature increase.
It aims to keep the rise between 1.5 - 2 degrees celsius.
The agreement is reviewed every 5 years and mbobilizes finance to developing nations to mitigate climate change impact for them, as well as prepare them for extreme situations.
Each party updates their progress via a Nationally Determined Contribution (NDC).

An annual event involving all parties in the UNFCCC.
Each party's progress on tackling global warming as part of the Paris Climate agreement is reviewed and assessed.
Further actions and strategies for reducing emissions and supporting low-carbon options are discussed and agreed.

Created by the UN to provide governments at all levels with with scientific information to help develop climate policies.
Provies reports into international climate change negotiations.
An organization of governments that are members of the UN or the World Meteorogical Organization (WMO).

Greenhouse gases are a group of gases contributing to global warming. Carbon is often used as a broad term to refer to the impact of all types of emissions and activities on global warming. CO2eq is a measurement term used to measure this impact.
The international community, in groups such as the UNFCCC, has come together to limit the impact of global warming by reducing emissions, aiming for a 'preferable' lower limit of 1.5°C.
This was agreed through the UN IPCC in 2015 in the Paris Climate Agreement and is monitored at the regular COP event.
Everything we do emits carbon into the atmosphere, and our goal is to emit the least amount of carbon possible.
This constitutes the first principle of green software: carbon efficiency, emitting the least amount of carbon possible per unit of work.