23 November 2021 - News

New PARIS REINFORCE study on warming outcomes of current policies and pledges

On Monday, 22 November, a new PARIS REINFORCE study was published in Nature Climate Change (Sognnaes et al., link), exploring where policies currently deployed as well as targets promised by countries to the UNFCCC would take us.

Our study uses a diverse modelling ensemble as well as various ways of “projecting” efforts into the future, and has made significant efforts to “streamline” inputs across all tools (see Giarola et al., here), with a view to ensuring robust findings.

All our scenarios produce a median warming of between 2 and 3°C in 2100. This is an important finding in the aftermath of COP26, during which several studies confidently estimated a warming of 2.7°C or 2.4°C in 2100, if either current policies or Nationally Determined Contributions (NDCs) respectively are projected into the future.

Our study instead finds that the uncertainties are much greater, projecting a 2.3-2.9°C or 2.2-2.7°C of warming, respectively.

Current pledges falling short of the Paris temperature goals is no big news. But, considering how the IPCC and its latest report on the climate system (WGI of the 6th Assessment Report) recently made clear what the world might look like in 1.5, 2, or 4°C of global warming, our research has two key takeaways.

First, the false precision to climate outcomes given during COP26 may lead countries to believe they are making good progress, when the opposite may indeed be the case.

Second, despite our research focusing only on current policy efforts (i.e., excluding the uncertainties of future technological miracles, behavioural changes, increased ambition, etc.), the large uncertainties found indicate that current policies and policy pledges can still lead to warming outcomes (anywhere between 2 and 3 degrees Celsius) with markedly different climate consequences and implications for society and the natural system.

Among others, we also highlight that emissions are more sensitive to the choice of tool than to the assumed mitigation effort, highlighting the critical role of the tools used to underpin countries’ climate policy targets. Moreover, we discuss that the concept of carbon prices, which is widely used in climate science to represent policy, leads to energy systems with higher needs for large-scale deployment of yet immature solutions like carbon capture and storage. In contrast, explicitly analysing real-world policies indicates higher deployment of renewable energy technologies and electric vehicles, i.e. technologies already available.

Considering the findings of another project study on the value of carbon capture and storage compared to renewables, published in One Earth (Grant et al., link), one may argue that modelling tends to display a bias for ‘technological miracles’ that have still been failing us, and against already available technologies that have confounded all expectations during the last decade. Meaning that, with the right ambition and actions, decarbonising our energy systems may be closer to our grasp than we tend to assume.