What are carbon offsets?

Carbon offsets are a way for travelers to compensate for the portion of greenhouse gas emissions generated from their travel by funding a project that aims to reduce emissions somewhere else in the world. For example, a traveler can buy a carbon offset alongside a plane ticket purchase. This carbon offset will contribute to support a clean energy or ecosystem protection project that would not have happened otherwise (in technical terms, the greenhouse gas savings are additional to business as usual scenario – that is, the project would not have happened without the funds).

There are two kinds of offsets: compliance and voluntary. Compliance carbon offsets are those traded in state-created carbon markets like the European Trading Scheme, where a firm (say a power producer) can meet its obligations to reduce greenhouse gas emissions by purchasing a credit or offset from another firm or from a certified offset provider in another jurisdiction. Voluntary offsets are those individuals or firms buy in an effort to compensate up for the amount of carbon generated by taking flights, but not as a part of a regulated emission reduction. These are the ones available for individuals to purchase to offset flights or other emissions.

Why are offsets an inadequate response to the climate crisis?

The use of carbon offsets remains controversial amongst experts. The first issue is that keeping warming below 1.5°C or 2°C requires strong emissions cuts, beginning in the developed world, which needs to achieve actual zero emissions as soon as possible. Recent research found that governments are on track to produce 120% more fossil fuels by 2030 than would be consistent with the goals of the Paris Climate Agreement. We need to drastically reduce the use and production of fossil fuels, period.

The most important question we must ask is: are carbon offsets contributing to keeping fossil fuels in the ground at the scale needed to achieve the goals of the Paris Climate Agreement? The answer is no.

There are problems of mis-calculation and over-estimation of emission reductions from offsets:

Carbon offsets require emission reductions that are additional to the status quo. But a 2016 study concluded that 85% of offsets certified under the Clean Development Mechanism (a compliance mechanism) likely did not contribute additional emission reductions (see also McNish 2012, Wara 2007, Donoghue 2010). Another 2015 study found that 75% of credits issued were unlikely to represent emission reductions. A 2018 assessment of forest-based carbon offsets by the Auditor General for the Government of Norway (Norway is a major supporter of forest-conservation based carbon offsets), concluded that the effort is plagued with difficulties, including “considerable uncertainty over climate impact” as well as ongoing concern about the social impacts of forest carbon-offsets. It states: “there is inadequate follow-up of social and environmental safeguards regarding Indigenous Peoples rights, poverty alleviation and preservation of natural forests”. A 2018 systematic review of the scientific literature on efforts to Reduce Emissions from Deforestation and forest Degradation  also found mixed results, with some indication of moderate impact at the local level in terms of forest cover; they highlight the need for further research.

Mechanisms like offsets delay meaningful action needed to keep warming to below 1.5 degrees:

Writing in Nature in 2012, renowned climate scientist Kevin Anderson makes the following points: offsetting emissions does not lead to behavioral change regarding air travel, instead taking flights and buying offsets sends the wrong market signal. It incentivizes companies to continue to extract oil, expand airports and delay mitigation efforts. Rather, staying on the ground incentivizes the development of better videoconferencing equipment, high-speed rail and so forth. Offsets do not tend to encourage the rapid transformation of travel infrastructure necessary to meet the Paris Agreement goals.

While Anderson is focused on individual offsets, similar patterns are found in the compliance markets. Created under the Kyoto Protocol, the Clean Development Mechanism, was meant to kickstart a clean energy transition in the Global South, funded through the purchase of credits by countries in the Global North (to help them meet their emission reduction targets). Writing again in Nature, Wara summarized that many of the reductions failed to establish a trajectory toward a low‐carbon energy infrastructure in the Global South. For example, the Clean Development Mechanism created offsets that funded the building of more efficient coal plants.

Climate justice scholar Patrick Bond (2015) argues that schemes like offsets “shift problems around spatially, without actually solving them” further allowing the North to “steal more of the world’s environmental carrying capacity – especially for greenhouse gas emissions”.

Offsets can have negative social impacts:

Because forests and other ecosystems sequester carbon, one type of offset involves the conservation of forests or ecosystems. These offsets are often framed as win-wins for both biodiversity conservation and climate change mitigation, as well as a win for poverty alleviation. While above we highlight questions about climate mitigation, there is a large body of research showing problems can occur with these types of offsets in terms of their social impacts. Impacts include large-scale evictions or dispossessions, in countries like Uganda, Tanzania, and Kenya. There is also evidence that the benefits of these schemes accrue to local elites, and increases inequality in communities in countries like Mexico and Costa Rica.

What about certified offsets?

When buying offsets, it is important that they are certified by recognized standards (e.g. Gold Standard) to avoid unverified projects and scams. The David Suzuki Foundation and the Pembina Institute have listed some recommendations for potential offset buyers.

Nonetheless, there is a high level of uncertainty surrounding carbon offset projects, even when they are certified by recognized foundations like the Gold Standard. For example, Wang and Corson (2015)  investigated a Kenyan cookstove project funded through carbon offsets. They found some benefits (e.g. positive respiratory health outcomes from improved cookstoves), but also major issues. They found that four out of the 15 improved cookstove users either never used them or stopped using them, while three removed them from their kitchen, significantly reducing the claimed carbon savings. The authors conclude that while they may have led to improvements in cooking time, smoke level and reduced labour burden, the projects largely benefited Northern counterparts.

What about the benefits?

While we highlight problems, we recognize that offsets can have positive results. The following benefits are taken from Becken, S., & Mackey, B. (2017). Journal of Air Transport Management.

“offsetting projects present an important opportunity for airlines to contribute to helping others reduce GHG emissions that would otherwise occur, along with the co-benefits of biodiversity protection and sustainable development. Depending on the type of project, funds raised by airlines, either through voluntary offsetting or as part of a sector agreement, could be an important component of a comprehensive cross-sectorial approach to avoiding future fossil fuel and biomass emissions.”

“Air travel seems perfectly placed to generate additional revenue for ‘environmental donations’ that can support climate mitigation projects.”

“Airlines already have built partnerships with carbon offsetting companies and particular projects, for example on forest protection. While these can be fruitfully continued and expanded, it is critical for their long-term credibility that airlines ensure the climate change benefits of these schemes are correctly communicated to their customers.”


Becken, S., & Mackey, B. (2017). What role for offsetting aviation greenhouse gas emissions in a deep-cut carbon world? Journal of Air Transport Management, 63, 71-83. doi:10.1016/j.jairtraman.2017.05.009

Beymer-Farris, B.A., Bassett, T.J., 2012. The REDD menace: resurgent protectionism in Tanzania’s mangrove forests. Glob. Environ. Change 22 (2), 332–341.

Bond, P. (2015, January). PDF. Manchester.

Cavanagh, C., Benjaminsen, T.A., 2014. Virtual nature, violent accumulation: the ‘spectacular failure’ of carbon offsetting at a Ugandan National Park. Geoforum 56, 55–65.

Chomba, S., Kariuki, J., Lund, J. F., & Sinclair, F. (2016). Roots of inequity: How the implementation of REDD+ reinforces past injustices. Land use Policy, 50, 202-213. doi:10.1016/j.landusepol.2015.09.021

Nel, A., Hill, D., 2013. Constructing walls of carbon–the complexities of community, carbon sequestration and protected areas in Uganda. J. Contemp. Afr. Stud. 31 (3), 421–440.

Osborne​, T.M., 2011. Carbon forestry and agrarian change: access and land control in a Mexican rainforest. J. Peasant Stud. 38 (4), 859–883.

Wang, Y., & Corson, C. (2015). The making of a “charismatic’ carbon credit: Clean cookstoves and “uncooperative’ women in western kenya. Environment and Planning a, 47(10), 2064-2079. doi:10.1068/a130233p