Natural Climate Solutions (NCS) versus Nature-Based Solutions (NBS)
“Natural climate solutions” are actions to protect, sustainably manage and restore natural and modified ecosystems in ways that mitigate climate change, while also addressing other societal challenges. The term is more or less interchangeable with “nature-based solutions.” The difference between the two terms is often one of emphasis. Those who use the former place emphasis on the benefits such actions have in the fight against climate change, while those who use the latter place more emphasis on the broad range of benefits that such actions can have for adaption, human well-being and biodiversity.
The COVID19 crisis is spurring an examination of how humankind’s destruction of nature is linked to, among other health issues, the spread of corona viruses. There has also been widespread coverage of the positive environmental results that are already being seen as a result of the economic downturn, although most pieces explain why this is not cause for celebration. In the coming months, as governments devise economic recovery plans, there will be a renewed focus on how nature-based solutions can improve health, create jobs (especially in rural communities) and build more resilient economies.
However, the role of natural climate solutions in the fight against climate change continues to be essential. Natural climate solutions can cost-effectively provide roughly a third of the climate action needed by 2030 and, unlike other carbon removal technologies, are available and proven now. There is a growing understanding that we cannot limit the rise of global temperature below 2 degrees Celsius and achieve ‘net-zero’ emissions by mid-century – the goals set forth by the Paris Agreement – without major investments in natural climate solutions today.
Critically, investments in natural climate solutions must be in addition to, not instead of, a transformation of the energy sector. However, the land sector is the only sector that can move from being a net source of emissions to a net sink. Current land use is responsible for a quarter of greenhouse gas emissions today; but it could contribute up to a third of the emissions reductions needed by 2030.
What the Science Says
The seminal scientific report underpinning the mitigation potential of natural climate solutions was published in the Proceedings of the National Academy of Sciences in 2017. Natural Climate Solutions, led by Dr. Bronson Griscom and scientists from 19 organizations, found that ‘NCS can provide over one-third of the cost-effective climate mitigation needed between now and 2030 to stabilize warming to below 2°C’. Allowing for future food, fuel and fibre requirements, the report found much of that natural mitigation — be it protecting mangroves, restoring forests or better managing farms — could be delivered at or below $10 per tonne of CO2.
Following this report, there was immediate recognition that natural climate solution science had to get more regional and more sophisticated. The Griscom paper had captured the size of the prize; but translating that into utility has been the focus of a new wave of scientific research in the period since. Prior to the Griscom paper, in 2015, only three academic papers were dedicated to natural climate solutions; in 2019 alone, there were more than 100.
In 2018, working with national-level data sets in the U.S., Fargione et al quantified the potential of 21 natural climate solutions to increase carbon storage and avoid emissions — largely through reforestation and improved land-management. Finding a maximum yearly potential of the equivalent of 21% of current net annual emissions, the report confirmed that despite being at the apex of industrialized nations, a significant part of low-cost US climate action can come from natural climate solutions.
Griscom’s team has more recently focused on tropical countries, which make up roughly 60% of the natural climate solution pie, but which often lack their own research capacity and tend to have large agrarian sectors as a proportion of domestic emissions. In January, they found that half of 79 tropical countries can mitigate over 50% of their national GHG emissions cost effectively with NCS; in more than a quarter, cost-effective potential from natural climate solutions was greater than national emissions. Another recent equatorial-focused paper found that just ten tropical countries comprise 55% of potential low-cost abatement from tropical reforestation through to 2050.
Challenges Facing Natural Climate Solutions
Despite this potential, natural climate solutions face significant challenges, most of which are associated with establishing a value for the protection, restoration and sustainable management of natural and modified ecosystems that outcompetes the value of destroying them, such as unsustainable agriculture and mining.
In the absence of a robust market that values the full range of services forests and other ecosystems provide – in terms of carbon storage, water provision, climate regulation, and biodiversity – they are generally considered more valuable for timber, cropland, or pasture than they are as standing, healthy, climate-protecting systems.
At the moment, less than 8% of public climate finance flows toward natural climate solutions. And although the land-use sector is referenced in the national climate pledges under the Paris Agreement – known as nationally-determined contributions, or NDCs – of 128 countries, these rarely describe comprehensive approaches to land use, there are few concrete actions on the ground, and almost no targets. Only 27 out of 168 countries included natural climate solutions in the first round of NDCs. There is significant room for improvement on this front as countries work to update or prepare new NDCs this year.