The Problem With "Green" Monetary Policy

As an alarming new United Nations report shows, climate change is probably the biggest challenge of our time. But should central banks also be worrying about the issue? If so, what should they be doing about it?

Central-bank representatives who do decide to make public speeches about climate change cannot deny the scale and scope of the problem; to do so would be to risk their own credibility. But the same is true when central bankers feel obliged to discuss the distribution of income and wealth, rising crime rates, or any other newsworthy topic. The more that central banks’ communications strategy focuses on trying to make themselves “popular” in the public’s eyes, the greater the temptation to address topics outside their primary remit.

Beyond communicating with the public, the question, of course, is whether central banks should try to account for environmental considerations when shaping monetary policy. Obviously, climate change and corresponding government policies in response to it can have powerful effects on economic development. These consequences are reflected in all kinds of variables – growth, inflation, employment levels – that will in turn affect central-bank forecasts and influence monetary-policy decisions.

Likewise, natural disasters and other environmental events – actual or potential – can pose implicit risks to entire classes of financial assets. Regulators and supervisors charged with assessing risk and associated capital needs must take this environmental dimension into account. At a minimum, the high uncertainty stemming from these risks implies a huge challenge for assessing the stability of the financial system and corresponding macroprudential measures. And these risk factors are also increasingly relevant for monetary-policy decisions, such as when central banks should buy bonds or (in some cases) equities.

But the growing public demand that central banks contribute more actively to the fight against climate change leads to a different dimension. In theory, central banks could introduce preferential interest rates for “green” activities – thus driving up the prices of “green bonds” – while adopting a more negative attitude toward noxious assets, such as those tied to fossil fuels. And yet, assessing whether and to what extent an asset is environmentally harmful or helpful would be extremely difficult.

Putting aside these more technical issues, the broader question remains: Should central banks assume responsibility for implementing policies to combat climate change? A number of prominent central bankers have already argued that they should. And current proposals for extending central banks’ mandate have come on top of growing concerns about income distribution and other issues tangentially related to monetary policy.

One is reminded of an ironic comment by the great Chicago School economist Jacob Viner.

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