While some of the costs of climate change won’t be incurred for centuries, the actions to mitigate them need to be taken today. Over such a long timespan, small changes in discount rates can drastically change the attractiveness of such investments. This column presents estimates of appropriate discount rates for very long time horizons. The long-run discount rate for one important risky asset class – real estate – is estimated at 2.6%. This provides an upper bound on long-run discount rates for climate change abatement, one that is substantially lower than some of the rates currently being employed.
Stefano Giglio, Matteo Maggiori, Johannes Stroebel, Andreas Weber, 23 January 2016
Adriana Kocornik-Mina, Thomas McDermott, Guy Michaels, Ferdinand Rauch, 21 January 2016
During the past couple of months alone, floods have displaced 100,000 people or more in Kenya, in Paraguay and Uruguay, and in India, as well as more than 50,000 people in the UK. And rising sea levels due to climate change loom. This column assesses the risk and the challenges for policymakers. It details the effects of flooding in cities around the world, showing that economic activity is concentrated in low-elevation urban areas, despite their much greater exposure to flooding. And worryingly, economic activity tends to return to flood-prone low-lying areas rather than relocating.
Stefano Giglio, Matteo Maggiori, Johannes Stroebel, Andreas Weber, 29 November 2015
The optimal investment to mitigate climate change crucially depends on the discount rate used to evaluate the investment’s uncertain future benefits. The appropriate discount rate is a function of the horizon over which these benefits accrue and the riskiness of the investment. In this paper, we estimate the term structure of discount rates for an important risky asset class, real estate, up to the very long horizons relevant for investments in climate change abatement. We show that this term structure is steeply downward-sloping, reaching 2.6% at horizons beyond 100 years. We explore the implications of these new data within both a general asset pricing framework that decomposes risks and returns by horizon and a structural model calibrated to match a variety of asset classes. Our analysis demonstrates that applying average rates of return that are observed for traded assets to investments in climate change abatement is misleading.
Richard S J Tol, 17 December 2015
The 21st Conference of the Parties (COP21) to the United Nations Framework Convention on Climate Change has successfully negotiated a Paris Agreement. International climate policy will be shaped by the events in Paris for years to come. This column highlights three key developments.
Ejaz Ghani, Arti Grover Goswami, William Kerr, 18 November 2015
Urbanisation in India is taking many twists and turns. Organised manufacturing is moving out of urban areas, while unorganised manufacturing is transitioning towards urban areas. As the fourth greatest energy consumer in the world, how the country manages this ongoing industrialisation and urbanisation process will have important environmental implications. This column looks at the relationship between growth, geography, and energy efficiency in manufacturing in India. Electricity consumption per unit of output has declined in urban and rural areas, but these overall trends mask substantial variation between states and substantial potential for further efficiency improvements in energy-intensive industries.
Cristina Cattaneo, Giovanni Peri, 14 November 2015
Climate change can affect agricultural productivity and the incentives of people to remain in rural areas. This column looks at the effects of warming trends on rural-urban and international migration. In middle-income economies, higher temperatures increased emigration rates to urban areas and to other countries. In very poor countries, however, higher temperatures reduced the probability of emigration to cities or to other countries, consistent with the presence of liquidity constraints.
Scott Barrett , Carlo Carraro, Jaime de Melo, 10 November 2015
This year, for the first time ever, nearly all of the world’s countries are making pledges to help limit future climate change. As of 1 October, 147 countries (representing about 85% of global emissions) have submitted their Intended Nationally Determined Contributions. These pledges, if carried out in full, are expected to lower emissions relative to the ‘business as usual’ forecast. However, they are not expected to prevent emissions from increasing above today’s level through 2030. To meet the global goal of limiting mean global temperature change to 2°C relative to the pre-industrial level, much more will need to be done after 2030. Eventually, emissions will have to fall to zero worldwide – either that, or countries will need to remove carbon dioxide directly from the atmosphere. This column introduces a new Vox eBook that looks into what needs to be done to build a climate regime that is both workable and effective.
Lucas Bretschger, 11 October 2015
There is reasonable hope that the upcoming United Nations Conference on Climate Change in Paris (COP21) will reach a consistent global climate agreement. What makes the negotiations particularly difficult is not economic efficiency, but the equity implications of climate policy. This column presents a framework for incorporating equity concerns into policy design. Building from four equity principles, it reduces the complex problem of international burden sharing to a simple rule tied to a single metric.
Richard S J Tol, 17 September 2015
The international climate negotiations have moved away from targets such as keeping warming below 2°C in favour of more realistic goals. This column presents new evidence on the economic impacts of climate change. The initial impacts of climate change on welfare might be positive, but in the long run the negative effects dominate, and will be substantially higher in poor countries. Poverty reduction therefore complements greenhouse gas emissions reduction as a means to reduce the impacts of climate change.
Arvind Subramanian, 16 July 2015
In December, the 21st United Nations Climate Change Conference will be held in Paris. This column discusses how India – despite its image as a recalcitrant negotiator – has exhibited considerable initiative towards improving its environmental footprint in recent years. Along with a host of actions targeting emissions, deforestation, and alternative energy source, India has surpassed many developed nations in responding to recent declines in international energy prices. These efforts mean India will be able to make a substantial contribution towards the success of the negotiations in Paris
Richard Layard, Gus O'Donnell, Nicholas Stern, Adair Turner, 08 June 2015
If clean energy were cheaper than dirty energy, climate change would halt. Making clean energy cheaper is a problem – like putting a man on the moon – that can be cracked if the effort is properly organised and financed. This column proposes a ten-year ‘Global Apollo Programme’ to achieve the necessary price reversal.
Catherine Hausman, Ryan Kellogg, 15 May 2015
The economic and environmental impacts of the US fracking boom are hotly debated. This column argues that there’s been a large positive impact on the US economy, estimating that the benefits to producers and consumers totalled $48 billion in 2013, or around one-third of 1% of US GDP. The climate change impacts have been large, but they do not outweigh the private gains. However, a lack of data on the impacts to water, air, and seismic activity hamper policymakers effectively targeting the areas of greatest concern and hamper them drawing up effective regulation.
Jason Furman, Ron Shadbegian, Jim Stock, 25 February 2015
The cost of delaying climate action has been studied extensively. This column discusses new findings based on a meta-analysis of published model runs. A one-decade delay in addressing climate change would lead to about a 40% increase in the net present value cost of addressing climate change. If anything, the methodology used in this analysis could understate the cost of delay. Uncertainty and the possibility of tipping points provide a motivation for more action as a form of insurance against worse outcomes.
Carlo Carraro, 07 February 2015
China and the US have recently agreed to reduce their greenhouse gas emissions. This column asks what quantifiable impact the new targets will have, whether they are any better than previous approaches, and if so, whether they are enough to avoid dangerous climate change. While insufficient for keeping temperature increase below the 2°C limit, the US and China’s bilateral commitments are a step in the right direction, and form the basis for a stronger international agreement in Paris later this year.
Jean-Marie Grether, Nicole A. Mathys, Caspar Sauter, 31 January 2015
Spatial inequalities in territorial-based greenhouse emissions matter in terms of regulation, both at the international and subnational levels. This column decomposes these inequalities worldwide for the two major greenhouse gases over the period 1970–2008. Within-country inequalities are larger, and rising, while between-country inequalities are smaller and falling. Moreover, social tensions arising from the discrepancy between the distribution of emissions and the distribution of damages appear to be larger within than between countries, and larger for carbon dioxide than for methane.
Valentina Bosetti, Jeffrey Frankel, 24 November 2014
Many countries have announced emissions targets for 2020. To evaluate which countries are doing their fair share, this column proposes a ‘scorecard’ approach based on three principles of fairness in climate change mitigation: latecomer catch-up, progressivity, and cost. The authors find that most countries’ targets, including those of China and the US, are in line with what such a scorecard would suggest.
David F. Hendry, 27 October 2014
Climate change has been the main driver of mass extinctions over the last 500 million years. This column argues that current evidence provides a stark warning. Human activity is producing greenhouse gases, and as a consequence global temperatures and ocean heat content are rising. Such trends raise the risk of tipping points. Economic analysis offers a number of ideas, but a key problem is that distributions of climate variables can shift, invalidating stationarity-based analyses, and making action to avoid possible future shifts especially urgent.
Rick van der Ploeg, Aart de Zeeuw, 31 July 2014
Many ecological systems feature ‘tipping points’ at which small changes can have sudden, dramatic, and irreversible effects, and scientists worry that greenhouse gas emissions could trigger climate catastrophes. This column argues that this renders the marginal cost-benefit analysis usually employed in integrated assessment models inadequate. When potential tipping points are taken into account, the social cost of carbon more than triples – largely because carbon emissions increase the risk of catastrophe.
Emanuele Massetti, Elena Ricci, 23 July 2014
Concentrated solar power generation in Northern African and Middle Eastern deserts could potentially supply up to 20% of European power demand. This column evaluates the technological, economic, and political feasibility of this idea. Although concentrated solar power is a proven technology that can work at scale, it is currently four or five times more expensive than fossil fuels. Concentrated solar power could play an important role in Europe’s energy mix after 2050, but only if geo-political challenges can be overcome.
Richard S J Tol, 25 April 2014
The IPCC’s Fifth Assessment Report estimates lower costs of climate change and higher costs of abatement than the Stern Review. However, current UN negotiations focus on stabilising atmospheric concentrations of greenhouse gases at even lower levels than recommended by Stern. This column argues that, given realistic estimates of the rate at which people discount the future, the UN’s target is probably too stringent. Moreover, since real-world climate policy is far from the ideal of a uniform carbon price, the costs of emission reduction are likely to be much higher than the IPCC’s estimates.