The global market for carbon offsets is expected to grow up to 50 times by mid-century, driven in part by the implementation of the UN-based Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). CORSIA intends to cap international aviation CO2 emissions at 2019 levels once air transport demand returns to pre-pandemic volumes. While innovations in aircraft design, sustainable fuels and air traffic management are all expected to help reduce the emissions intensity of aviation, the program requires that any remaining emissions growth above the cap be offset.
As a participating country in CORSIA, Canada has committed any aircraft operators conducting flights between Canada and other CORSIA-participating nations to chip in to the global offsetting requirements. The International Civil Aviation Organization (ICAO) will determine how much CO2 each operator must offset each year, using a formula based on sectoral emissions growth above the 2019 baseline.
CO2 emissions associated with international air transport account for two-thirds of Canada’s total aviation emissions, with domestic air transport (including military aviation) accounting for the remainder. It is not yet clear whether Canada intends to include offsets within its domestic aviation emissions mitigation strategy (which is presently being revised).
The federal government’s 2012 Action Plan to Reduce Greenhouse Gas Emissions from Aviation did not actually seek a net reduction in GHG emissions from aviation, but rather set out a goal of achieving fuel-efficiency improvements of two per cent per year through 2020, after which it committed to meeting a similar type of cap on emissions growth as that faced by international aviation under CORSIA. Canada’s 2021 nationally determined contribution (our nation’s plan to reduce GHG emissions filed as part of the Paris Agreement) sought to bring domestic transportation within the Canadian Net-Zero Emissions Accountability Act, but it remains to be seen whether carbon offsets will be a tool available for domestic aircraft operators to meet Canada’s 2050 net-zero targets.
The basic idea underlying flight carbon offsets is that purchasers can pay for an equivalent amount of CO2 to be sequestered as that emitted by an aircraft, thereby neutralizing a flight’s climate impact. Historically, offsets have been marketed to individuals on a trip-by-trip basis. A recent consumer survey in the U.S. suggests that only about eight per cent of Americans had previously purchased flight carbon offsets, while a third expressed willingness to pay for them. While consumers ultimately will bear the cost of offsetting, the new UN-based program will shift much of the burden to airline operators, who must purchase wholesale offsets to cover annual emissions growth above the CORSIA baseline. The hope is that such an offsetting scheme will ensure the aviation sector’s annual climate footprint remains at pre-pandemic levels – even once the sector fully recovers and grows thereafter.
In theory, if every tonne of anthropogenic CO2 emitted around the world were genuinely offset, we would reach net-zero, effectively hitting pause on global warming. In practice, the framework governing offsets is riddled with loopholes and in the case of the aviation sector falls far short of its climate-mitigation targets. It’s time for the aviation sector (and regulators) to wake up to the fundamental reality that mitigating aviation’s climate impact will require actual emissions reductions.
There are three main reasons why trying to buy our way out of the problem through carbon offsets is not going to cut it.
First, most carbon offsets don’t work. When conventional jet fuel is burned, it emits carbon that not so long ago was sequestered deep in the earth’s crust, where it had safely been stored for millions of years. It will take hundreds of years for most of that emitted carbon to be absorbed back into ocean carbon sinks. Twenty per cent of that carbon will remain in the atmosphere for thousands of years, all the while continuing to warm the atmosphere. So, to truly offset the carbon emissions from a flight, one needs to ensure that the CO2 being removed from the atmosphere will stay out for hundreds, if not thousands, of years. Yet that’s not a guarantee most offset projects can make.
Today, most offsets rely on biological carbon sequestration, usually in the form of tree planting or forest conservation, which usually fail to keep carbon out of the atmosphere for that long. As an example, during last summer’s unprecedented wildfires in the American West, hundreds of thousands of acres of forest protected through carbon-offset financing went up in smoke, effectively nullifying those offsets.
This gets to a second problem, known as “additionality.” To serve as a genuine offset, we need to ensure that CO2 removed from the atmosphere as part of an offset project was not already going to be removed anyway. Otherwise, we end up with false carbon accounting. Yet, studies have found that most offset project simply do not meet this threshold. Many of the projects funded through offset financing are things that need to happen anyway – in addition to reducing emissions elsewhere – to mitigate climate change. Within the Intergovernmental Panel on Climate Change (IPCC) future scenarios for a safe climate, we need not only to bring annual CO2 emissions to zero within a few decades; we also need to remove many gigatonnes of CO2 each year on top of that to reduce the impact of legacy emissions. So, if we fund carbon removal projects now through offsets, it merely adds to our CO2 removal tab later this century.
There’s no way around it: actual emissions have to decline. We’re gambling with our future if we pin our hopes on negative-emissions technologies decades from now to do the work which should be done today.
The third main problem with offsets is their limited influence on aviation demand from the highest-emitting consumers. Those whose flights create the most emissions – frequent and corporate flyers – are the ones most able to absorb the additional costs associated with flight offsets. As such, offsets allow an individual or firm to justify carbon-intensive activities such as flight travel at a time when climate mitigation requires behavioural change across society. Frequent use of aviation is anathema to climate action, at least for now while the global supply of sustainable aviation fuels is but a fraction of the global fuel mix, and while emissions-free commercial aircraft are still very much at a conceptual stage.
There are other reasons why flight carbon offsets have raised concerns amongst experts: Carbon-offset financing has been used for questionable initiatives in the Global South, in some cases resulting in people being displaced from their lands. Further, offsets do not address the non-CO2 emissions from aircraft, meaning carbon offsets are addressing only a portion of aviation’s full climate impact.
If we really want to get serious about mitigating the climate impact of aviation, we need to reconsider the sector’s reliance on carbon offsets and focus instead on real emissions reductions through a range of additional policy tools.
This could include:
- demand-management strategies (wherein transport planners seek to limit the number of flights or passenger-revenue kilometres based on annual emissions-reduction objectives);
- mode shifting in short-haul transport markets (including bans on short-haul flights where sustainable alternatives are available);
- “flex regs” on aircraft producers and airline operators (where commercial firms are given mandatory emissions-reduction targets but offered the freedom to achieve these however they wish, thus encouraging innovation);
- levies on private jets and frequent flying (thus increasing costs for the highest-impact aviation consumers), and:
- state-led investments in research and innovation in zero-emissions aircraft design and next-generation sustainable aviation fuels (rather than leaving this solely to the private sector).
These tools, along with existing efforts to improve aviation fuel efficiency, can help achieve real, measurable emissions reductions in the sector, as opposed to offsets, which are unreliable and speculative.