The 40% Study

The study demonstrates that the EU can achieve domestic emission cuts of 40% by 2020 and 90% by 2050 through radical energy efficiency, a shift to renewables, and the phase-out of fossil fuels and nuclear power. It argues that such a transition is technically possible and economically bearable, costing approximately 2% of the EU's cumulative discounted GDP between 2010 and 2020. To achieve climate justice, the report asserts the EU must also provide between €150 billion and €450 billion annually by 2020 to support mitigation in developing countries.

• The European Union can technically achieve greenhouse gas emission reductions of at least 40% by 2020 and 90% by 2050 without relying on carbon capture and storage (CCS), biofuels, offsetting, or new nuclear power.
• To meet its total mitigation obligation under the Greenhouse Development Rights (GDRs) framework, the EU would need to achieve 103% greenhouse gas reductions below 1990 levels by 2020, split between domestic action and international investment.
• The proposed mitigation scenario requires a dramatic shift in the energy mix: coal is to be entirely removed by 2035, nuclear power phased out by 2050, and renewables' share of primary energy increased from 10% in 2010 to 71% by 2050, led primarily by wind power.
• Significant transport transformations are necessary, including doubling the rail network by 2050, ensuring 80% of intra-EU flights under 1000 km switch to rail, and achieving full electrification of cars by 2050.
• Household energy demand can be reduced by 63% by 2050 compared to 2010 levels through a 5% annual retrofit rate for existing homes and the adoption of 'passive house' standards for new buildings.
• The EU's international financing obligations to developing countries for climate mitigation are estimated to be between €150 billion and €450 billion per year by 2020, representing 1.1% to 3.3% of the EU's projected 2020 GDP.
• The total Net Present Value (NPV) of the mitigation scenario relative to the baseline is €1.94 trillion, which is approximately 1.7% to 2% of Europe's cumulative discounted GDP between 2010 and 2020.

APA

Stockholm Environment Institute (2009). The 40% Study. https://www.sei.org/mediamanager/documents/News/Press-releases/40-percent-europe-climatestudy-foee.pdf.pdf

Chicago

Stockholm Environment Institute. The 40% Study. 2009. https://www.sei.org/mediamanager/documents/News/Press-releases/40-percent-europe-climatestudy-foee.pdf.pdf.

Wikipedia

{{cite report |author=Stockholm Environment Institute |title=The 40% Study |date=December 2009 |url=https://www.sei.org/mediamanager/documents/News/Press-releases/40-percent-europe-climatestudy-foee.pdf.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{stockholmenvironmentinstitute2009study, author = {{Stockholm Environment Institute}}, title = {{The 40\% Study}}, institution = {Stockholm Environment Institute}, year = {2009}, month = dec, url = {https://www.sei.org/mediamanager/documents/News/Press-releases/40-percent-europe-climatestudy-foee.pdf.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }