05 Aug 2021

What are science-based targets? (part 1)

Posted in: Reducing emissions

What are science-based targets?

science based targets text over an image of fernsPart 1 in a new series

Your boss has asked you for a science-based emissions reduction target – how do you get started? This series of articles will cover what you need to know.

Climate science and the carbon budget

The concept of science-based targets (SBT) emerged following the signing of the Paris Agreement in 2015. In New Zealand, SBTs are often referred to as science-aligned or climate-aligned targets. This is due to the term SBT being a trademark of the Science Based Target initiative (SBTi), so it can only be used if you have submitted your targets to this body for official validation. Regardless, for the sake of simplicity we’ll stick with the acronym SBT in this article.

At its most basic definition, an SBT is an emissions reduction target that aligns with climate science to contribute to the global goal of limiting warming to well below 2°C over pre-industrial levels – with the ideal being 1.5°C below (explore why we want to keep it to 1.5° here). As is often the case, that definition requires a bit of explanation to fully grasp what it means for you. So bear with us.

The Carbon Budget

The Intergovernmental Panel on Climate Change (IPCC) has calculated how much carbon dioxide it believes we can release into the atmosphere, at a global level, before we lock in a temperature rise of 1.5°. This capped amount of greenhouse gases, roughly one trillion tonnes of carbon dioxide equivalents, is called the carbon budget.

graphic illustrating the years of current emissions remaining that would use up the IPCC’s carbon budgets for different levels of warming: 1.5 degrees, 2 degrees and 3 degrees

Figure: Carbon budgets to stay within warming limits for 1.5 degrees, 2 degrees and 3 degrees

As you likely know, the Paris Agreement is a commitment to reach net zero emissions by 2050 and through the carbon budget we know how much carbon we can afford to emit over the next 29 years. The plan, as it stands, is to curb emissions growth immediately and then halve our emissions by 2030 to prevent more drastic action being required in later years. The closer we stick to the budget, the greater chance we have of limiting warming overall and the severity of climate change impacts.

Net Zero

The IPCC considers net-zero is achieved when carbon emissions from human activity are balanced globally by carbon emissions removals over a specified period.

Bar graph illustrating the neutralisation actions required to offset a company’s remaining/residual emissions, with the significantly higher emissions that would be produced without an SBT, between 2020 and 2050. If a company sets an SBT, neutralisation actions increase towards 2033, but then decrease between 2033 and 2050 as the residual emissions also decrease. Figure: Aligning with SBTI Net Zero Neutralize Residual Emissions

(Source: WWF, Beyond Science-Based Targets: A Blueprint for Corporate Action on Climate and Nature, December 2020)

SBTs in practice

An SBT works by aligning your emissions reduction targets, as an organisation, with the carbon budget. This requires you to calculate your full emissions profile, including through your supply chains, to work out your fair share of the remaining carbon budget. The end result is a bespoke emissions reduction target that is designed to track the IPCC’s global target.

The hard part comes next. SBTs are intentionally ambitious and require organisations to undertake and plan for substantial change in their current operations over the long term. The focus here is on reducing emissions at the source, rather than just offsetting them through carbon credits. It is intensive, but undoubtedly worth it. We will cover off how to set targets in Part 3 of this series, and how to action them in Part 4.

Line graph the emissions reductions needed to stay in line with a 1.5 or 2 degrees increase in warming, and an example organisation pathway to achieve them. Organisations may find that their emissions are initially higher than required, but then drop below the target level, to achieve the target over the long term.

Figure: Organisation pathways will vary depending on your unique profile

SBTs and emissions reduction tools

To set and implement an SBT requires a suite of carbon accounting and reduction tools. This is where our expertise comes in. We are the first CDP-accredited science-based targets partner in Australia and New Zealand, with experience advising and auditing organisations of all sizes on carbon management and reduction initiatives. We have worked with Fletcher Building, Synlait and NZ Post, among others, to help them set their SBTs.

The main difference between SBTs and other science-aligned programmes, such as Toitū carbonzero or carbonreduce, is the specific alignment with the global carbon budget over the long-term. The tools we use to calculate, set and action targets are effectively the same.

What about offsets?

Offsets are a great tool to compensate for unavoidable emissions. Using carbon credits in the short term will certainly help the atmosphere while you reduce, even if you aren’t counterbalancing everything. But they don’t count as part of a science-based reduction strategy. To truly achieve net zero, we must reduce emissions overall.


As mentioned upfront, you can only refer to your emissions reduction targets as being officially validated by SBTi, and listed on the SBTi website, if you officially submit to the SBTi for validation.  For more information on official validation, check out the submission section on their website.

You may decide to develop targets aligned to all the key SBTi criteria, but opt not to go through the official validation process.  For this, you may seek review by providers such as Toitū to confirm your targets align to the relevant criteria.

Once you’ve set your target(s), you need to implement plans to achieve them, and demonstrate progress against your target(s).  Toitū can provide verification services to confirm if your progress against target(s) is aligned to your stated, Science aligned targets.

In Part 2 of this series, we look at the benefits of SBTs and why you should consider committing to one. Keep reading here.

Want to know more?

Understanding the science behind strategic emissions reductions is just the beginning of decarbonisation. Read our other reduction stories here or:

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