Meeting Paris climate targets will require a substantial reallocation of global investment

Low carbon investments need to increase if the world is to achieve the Paris Agreement aim of keeping global warming below 2°C. A fundamental transformation of the global energy system can be achieved with a comparatively modest increase in overall investments. Shift of investments away from fossil fuels and toward renewables/energy efficiency is needed. Current incentives like the NDCs will not provide sufficient impetus for the “pronounced change” that are needed for the energy system.

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A new analysis by an international team of scientists led by IIASA shows that low carbon investments will need to markedly increase if the world is to achieve the Paris Agreement aim of keeping global warming well below 2°C.The authors find that a fundamental transformation of the global energy system can be achieved with a comparatively modest increase in overall investments. However, a radical shift of investments away from fossil fuels and toward renewables and energy efficiency is needed, including dedicated investments into measures to achieve the United Nations’ Sustainable Development Goals (SDGs).

As part of the Paris Agreement in 2015, many countries defined Nationally Determined Contributions (NDCs) designed to reduce their greenhouse gas emissions. The study confirms that current incentives like the NDCs will not provide sufficient impetus for the “pronounced change” in investment portfolios that are needed to transform the energy system.

To keep global temperature rise to 1.5–2°C, investments in low carbon energy and energy efficiency will likely need to overtake investments in fossil fuels as early as 2025 and then grow far higher. The low carbon and energy efficiency “investment gaps” calculated by the researchers are striking. To meet countries’ NDCs, an additional US$130 billion of investment will be needed by 2030, while to achieve the 2°C target the gap is US$320 billion and for 1.5°C it is US$480 billion. These investment figures represent more than a quarter of total energy investments foreseen in the baseline scenario, and up to half in some economies such as China and India. 

The researchers point out that energy system transformation investments to reduce greenhouse gases are an order of magnitude greater than those required to meet other SDGs, such as for energy access, clean water, air pollution, food security, and education. 

“We know that limiting global temperatures to well below 2°C demands that renewables and efficiency scale up rapidly, but few studies have calculated the energy investment needs for a fundamental system transformation, at least not with an eye toward 1.5°C and using multiple scientific modeling frameworks running side-by-side,” says IIASA researcher and lead author of the study David McCollum. 

The six scenario modeling tools used by the researchers, so-called integrated assessment models, are often employed to evaluate the costs, potential, and consequences of different energy, climate, and human development futures over the medium-to-long term. In this case the researchers collaborated within the framework of the Horizon 2020 project “Linking Climate and Development Policies – Leveraging International Networks and Knowledge Sharing (CD-LINKS)”. The project brings together leading international research organizations to explore national and global transformation strategies for climate change and their linkages to a range of sustainable development objectives. 

“This is the first scientific study to conduct a systematic and detailed analysis of the energy investment needs for futures including the very ambitious target of 1.5°C. We find that a 1.5C investment strategy will be quite different from one to reach 2°C. Particularly investments into energy transmission and storage as well as for renewables and efficiency would need to be scaled up more rapidly for reaching 1.5°C. On the other hand both targets (1.5°C and 2°C) will mean that upstream investments into coal extraction and unabated fossil power generation without carbon capture and storage will need to scale down rapidly to avoid further lock-in of the system into fossil fuel infrastructure,” says IIASA Energy Program Director Keywan Riahi. 

Outputs of this analysis provided crucial scientific underpinning for a methodology developed by and for the banking industry to improve their understanding of climate change, how it could impact business and how to better manage climate-related risks. The researchers are hopeful that their findings will be of use to national and global policy analysts and policymakers, as well as those in the private sector, working in the areas of energy, climate change and sustainability over the next several years. 

“It’s important for professionals in the finance sector to be aware how much more investment in low carbon solutions is needed if the world is to meet the Paris targets. The NDC pledges are a step in the right direction, though much deeper changes in the energy investment portfolio are clearly necessary,” says Elmar Kriegler, vice chair of the research domain “Sustainable Solutions” at the Potsdam Institute for Climate Impact Research (PIK) and one of the coauthors of the paper.

Many of the world’s largest economies have already agreed to place low carbon investments high on their priority lists. For example, as part of the recent G20 Hamburg Climate and Energy Action Plan for Growth, countries agreed “to create an enabling environment that is conducive to making public and private investments consistent with the goals of the Paris Agreement as well as with the national sustainable development priorities and economic growth”, thus reiterating an earlier agreement to mobilize US$100 billion per year for mitigation actions in developing countries. 

“Our work demonstrates that support on the order of US$100 billion would go a considerable way toward closing, maybe even completely cover, the low-carbon investment gap for developing countries; however, considerably up-scaled capital flows will be needed globally to meet the Paris Agreement targets. On top of that, developing countries will likely need support to cover the investment needs of other SDG targets, specifically energy access, clean water, air pollution, education and food security. Our study shows that climate change mitigation can have significant implications for the investments in these areas, on the order of tens to hundreds of billions,” says McCollum. 

Key insights of the analysis can be visualized in a user-friendly way with the CD-LINKS Energy Investment Visualization page, the development of which was led by Valentina Bosetti and Laurent Drouet of the Euro-Mediterranean Center on Climate Change (CMCC).


McCollum DL, Zhou W, Bertram C, de Boer H-S, Bosetti V, Busch S, Després J, Drouet L, Emmerling J, Fay M, Fricko O, Fujimori S, Gidden M, Harmsen M, Huppmann D, Iyer G, Krey V, Kriegler E, Nicolas C, Pachauri S, Parkinson S, Poblete-Cazenave M, Rafaj P, Rao N, Rozenberg J, Schmitz A, Schoepp W, van Vuuren D, & Riahi K (2018) “Energy investment needs for fulfilling the Paris Agreement and achieving the Sustainable Development Goals,” Nature Energy, doi: 10.1038/s41560-018-0179-z [].

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 642147 (CD-LINKS).



CD-LINKS is a research project that brings together a consortium of nineteen leading international research organizations from around the globe to explore national and global transformation strategies for climate change and their linkages to a range of sustainable development objectives. An important question for policy makers, in the G20 and beyond, is how to bring climate action into the broader sustainable development agenda. Objectives like energy poverty eradication, increased well-being and welfare, air quality improvement, energy security enhancement, and food and water availability will continue to remain important over the next several decades. There have been relatively few scientific analyses, however, that have explored the complex interplay between climate action and development while simultaneously taking both global and national perspectives. The CD-LINKS project will change this, filling the critical knowledge gap and providing much-needed information for designing complementary climate-development policies. The project aims to have a pronounced impact on the policy dialogue, both nationally and internationally: an important outcome of the project will be a list of country-specific policy recommendations for effectively managing the long-term transformation process. These recommendations will point out opportunities for policy synergies and at the same time respect political and institutional barriers to implementation.

Project details

  • Project title: “Linking Climate and Development Policies – Leveraging International Networks and Knowledge Sharing” (CD-LINKS)
  • Funding scheme: European Union Horizon 2020 Programme (EU H2020, grant agreement no. 642147)
  • Duration: 4 years (1 September 2015 – 31 August 2019)
  • Project coordinator: International Institute for Applied Systems Analysis, Austria
  • Project website: