As a side effect of the accelerated move towards the cloud, the software industry is contributing more and more to global warming. Companies took different commitments: Net-Zero, Carbon Neutral etc. Asim Hussain, Green Cloud Advocacy Lead @ Microsoft deciphers them during the Devoxx UK keynote. Understanding them will help developers move the needle for each type of commitment.

Global warming is tied to the amount of greenhouse gasses(GHG) in the atmosphere. But even though there are multiple GHGs(Methane has a 40 times bigger impact than CO2), the most common one is carbon dioxide (CO2). For brevity, they were normalized to Carbon Dioxide Equivalent(CO2eq or CO2e), so 1 tonne of methane can be called 40 tonnes CO2eq. Green Software Foundation, an entity chaired by Hussain, focuses on software as part of the climate problem, aiming to reduce carbon emissions as a result of software.

As everything emits CO2, the goal of green software engineers is to build the most carbon efficient software possible: extracting the maximum amount of value from every gram of CO2 applications are responsible for emitting. And as you can’t improve if you can’t measure, Hussain pointed to two measuring methods:

• GHG protocol: - calculating the total carbon footprint:

  • Scope 1: Direct emissions related to on-site fuel combustion or fleet vehicles.
  • Scope 2: Indirect emissions related to emission generation of purchased energy, such as heat and electricity.
  • Scope 3: Other indirect emissions from all the other activities you are engaged in. Including all emissions from an organization's supply chain, business travel for employees, and the electricity customers may consume when using your product.
    • Software Carbon Intensity (SCI) Specification: focussed on calculating a rate of emissions rather than a total

Nevertheless it is all about reducing emissions, as neutralizations are not permanent. He also points at the four manners in which emissions can be reduced:

Based on this four strategies the different trails to zero emission are drawn:

• Emissions 100% eliminated - not really feasible
• Carbon Neutral - 100% of the emissions are neutralized/ compensated
• Net-Zero: 90% eliminated, 10% permanently neutralized

The goals set by them are to reach 45% reduction by 2030 and net-zero by 2050. But in order to transform this into reality, it is important to have the correct perspective on the amount of CO2eq cost of your application. Hussain encourages the use of the cost per user rather than the total cost: 6g CO2eq/ user rather than 90 tonnes/ application. And in this way might it just become just another Service Level Objective for your application?

With really competitive targets by mid of the century, Hussain identifies himself as

someone who’s been working at the frontlines of enterprise organization trying everything he could to get investment into the right activities, at scale

Besides this, he is on a campaign of creating awareness of the impact the code we write has on GHG emissions and more about how we can design and build more sustainable software.