A FINANCIAL APPROACH TO CLIMATE RISK

• Robert Engle• Volatility Institute at NYU Stern• T20 Summit• May 27,2019
Version 3

CLIMATE ASSESSMENT• Scientists say the climate is changing• How bad will it be and what are the impacts on me and mychildren and their children?
• What will the governments of the world do?
• What new technologies might become available?

IS THE EARTH WARMING?
• How should we measure something like this? Time of day, time of year,
location, land, water, atmosphere? These are all complexities.

• The temperature changes are relative to the global average surface
temperature of 1961−1990.
• Source: IPCC AR5, data from the HadCRUT4 dataset (black), UK Met Office Hadley Centre, the NCDC MLOST
dataset (orange), US National Oceanic and Atmospheric Administration, and the NASA GISS dataset (blue), US
National Aeronautics and Space Administration.

OCEAN HEAT CONTENTGLOBAL SEA LEVELIS WARMING DUE TO THE SUN? NO!

THE ROLE OF GREENHOUSE GASES• The most important is CO2 or carbon dioxide. Also important
are methane(CH4), nitrous oxide(N2 O) and halocarbons.
• These gases absorb infra-red radiation that is re-radiated fromearth and act like a blanket around the earth.
• Carbon dioxide lasts a long time and is therefore the mostdangerous. Methane is very opaque to infra-red but decays
rapidly. We have acted to restrict CFCs to protect the ozone
layer; this also reduced GHG.

TEMPERATURE AND CO2

AN ECONOMIC VIEW OF THE
PROBLEM AND THE SOLUTION

EXTERNALITY• Carbon emissions are costless to the producer but impose
costs on others both in the short and long run.
• Solutions are to charge for emissions or to regulate emissions.
• Charging is complex and the correct price is hard to ascertain.
Mechanisms are cap-and-trade or carbon emissions tax.
• The charge should be global and should be comprehensive.

REGULATION• An alternative is regulation and subsidies• This risks making counter productive restrictions.
• It requires the regulator to set priorities• Examples are LED lights, CAFÉ standards, Biofuels

THE SOCIAL COST OFCARBONDEFINITION• It is the present discounted value of the welfare damages resulting
from an additional ton of CO2 emissions today.
• This assumes some baseline• It assumes a damage model• It assumes a discount rate
• It is the optimal Pigouvian tax and is also useful in cost benefit
calculations

DAMAGES - THREE TYPES• 1. MITIGATION COSTS ARE THE COSTS OF SLOWING EMISSIONS.
• Switching to renewable energy, changing consumption to lower carbon goods and services• 2. ADAPTATION COSTS ARE THE COSTS OF MANAGING CLIMATE CHANGE.
• Building seawalls, dams, firebreaks, medical defense against tropical diseases and insects.
Moving farms, cities, plants to higher, cooler locations. ‘Air conditioning the planet!’• 3. UNMANEAGABLE COSTS ARE THE IMPLICIT REMAINING COSTS OF CLIMATECHANGE• Extinction of species, severe weather, shorter life expectancy, massive population andspecies migration northward, destruction of natural environments.

IAM• The Integrated Assessment Models can be used for thiscalculation. These assume no mitigation and business as usual.
• Nordhaus gets $25/ton from this. Obama administration $45.
• Trump administration has used as little as $1.
• This can also be done with “top down” damages. Ricke etal.(2018) in Nature Climate Change estimate $417 .

RICKE’S APPROACH• We observe that countries in temperate zones have higher per
capital incomes and growth rates than either more tropical orcolder countries.
• If this is structural (a big but potentially defensible assumption)then global warming will have different impacts on different
regions of the world.
• The SCC is the sum of the global damages since a ton of carbon
emitted anywhere affects the whole planet.

SCC IN RICKE ET AL.

ECONOMISTS’ RECOMENDATION• A comprehensive global price for carbon emissions at a
substantial level would raise money that could reduce othertaxes or be rebated directly.
• It would encourage rapid shifts of resources to lower carbon
technologies producing new jobs.
• It would incentivize research and development of carbon
capture and clean energy.
• There are winners and losers, but it should produce the best
outcome from a social welfare point of view.

GOVERNMENT RESPONSE• Many governments are unwilling to take these steps.
• Near term problems “trump” long term problems.
• Electorate not clearly behind carbon pricing.
• Paris accord is limited.

• So the consequences will come upon us• unless we are rescued by the private sector• or by technological advancesWHAT CAN INVESTORS AND
COMPANIES DO?

THE STOCK MARKET• With accurate foresight of climate change, companies can adapt by
investing in lines of business and locations that will minimize costs ofclimate change.
• This includes energy efficiency but not carbon efficiency.
• (Why? Because it costs money and does not increase profits)• The stock market should give such firms higher valuations, leading tolower cost of capital.
• Outperformance would accrue only to investors who anticipated thegreening of a firm.

WHY MIGHT FIRMS INVEST IN
CARBON EFFICIENCY?
• Because it will pay off if a carbon price is eventually implemented.
• Because otherwise they may be hit with lawsuits for knowingly
destroying the planet.
• Because bond ratings may fall from failure to adapt to climate change• Because it should pay off in the long run if the climate becomes
terrible; long term investors will respond.
• Because it is the right thing to do and maybe shareholders andcustomers will see it this way too.

PUBLICLY AVAILABLE INFORMATION ON
CARBON EMISSIONS IS COMING.

SUSTAINABLE INVESTING• There is a great interest in sustainable investing.
• Sustainable products are based on ESG scores for• Environment (include climate factors and carbon factors)• Social• Governance• Portfolios and impacts are sensitive to data. Great need for betterdata especially on carbon emissions upstream and downstream.
• Performance measures indicate the costs.

WHY SHOULD INVESTORS BUY SUSTAINABLE
STOCKS? CLIMATE RISK

• If there is uncertainty about the evolution of the climate, then thestock market provides a way to hedge bad outcomes. (These arecalled Merton Hedge portfolios.)• Risk averse investors should hold outsized positions incompanies that will do well if the climate becomes worse thanexpected, and reduced positions in firms that will do badly if theclimate becomes worse than expected.
• This is a bet against the climate. It will reduce climate risk forthe investor. The investor should expect to pay for this insurance.

VOLATILITY INSTITUTE, NYU STERNDYNAMIC HEDGE PORTFOLIOS• Designing a portfolio that will protect against climate risk 50years in the future, however, is an impossible task.
• Nevertheless, there are many sustainable investment vehicles
offered in the market. We turn to evaluation of these.

• Then we will propose a dynamic strategy.

VOLATILITY INSTITUTE, NYU STERNPUBLICLY AVAILABLE PORTFOLIOS• GREEN ETFs
• ALTERNATIVE ENERGY• WIND• SOLAR• NUCLEAR• LOW CARBON• MORNINGSTAR SELECTED FUNDS• LOW EXPOSURE TO FOSSIL RESERVES• CARBON FOOTPRINT < .5*SP500• HIGH RANKING ON E MEASURE OF ESG• INTERNATIONAL SUSTAINABLE

VOLATILITY INSTITUTE, NYU STERNV-LAB CLIMATE RISKWHAT DO WE EXPECT?
• Sustainable and Environmentally sound investments are very popular.
Hence the prices are high.
• Other things being equal, we expect returns therefore to be low.
• We expect that these will differ from Markowitz optimal portfolios andtherefore have lower Sharpe Ratios, just as we would expect for anyinsurance.
• If the climate surprises the market and is worse than expected, thenthese portfolios should outperform.
• The benefit from climate investing is long term, not short term.

AMG YACKTMAN FUND

AMG YACKTMAN FUND (2011-PRESENT)ALTERNATIVE ENERGY ETF

PERFORMANCE OF V-LAB FUNDS
Average FF Alpha by Window Length
Category

1Y

3Y

5Y

EWMax

Alternative Energy

-5.22

-5.91

-10.97-7.43-20.69Fossil Fuel Free

-7.64

-6.03

-7.16

-6.64

-5.07

High Environmental Score

-9.17

-7.46

-8.23

-8.12

-4.09

International Sustainable-12.43

-5.95

-8.45

-6.55

-6.38

Low Carbon

-9.77

-6.54

-7.16

-6.92

-4.80

TWO OBVIOUS PROBLEMS• The cost of investing in sustainable funds appears high, as thealphas are typically worse than -5%/year.

• Unlike insurance, there is no guarantee that these funds will pay
off if the climate is bad.

forthcoming Review of Financial Studies

THE IDEA FOR A DYNAMIC HEDGE PORTFOLIO• When there is news that the climate is getting worse, whichstocks go up and which go down? This is the portfolio you wantto hold going forward.
• Ultimately you will hold a portfolio that outperforms in a badclimate state. It will naturally underperform if the climate does
not deteriorate.

NEWS• Textual analysis of Wall Street Journal stories over 20 years.
• Measure the similarity of the words and phrases to a collectionof climate change dictionaries.
• When there is news reported in the WSJ on climate change, thesimilarity is high,• Typically climate news is bad news.
• As a check we use an alternative series from Crimson Hexagon
which measures sentiment.

PORTFOLIOS• We consider portfolios that are weighted by characteristics such as carbon
footprint. We use several third party data sets.
• We seek factor mimicking portfolios that are maximally correlated with thetext variable.
• In sample, we get correlations of 0.4 when using sustainalytics E score. Outof sample this is only 0.2.
• Better data and more sophisticated estimation can potentially improve theseresults. Nevertheless, the method appears promising.

NEXT STEPS ON V-LAB• Create daily updates to climate news text measure• Show correlations of publicly traded sustainable funds with thismeasure.
• Using new data science methods find additional hedge
portfolios as factor mimicking versions of our text measure.
• Follow these on V-LAB.
• Expect these by September

CONCLUSIONS• The best solution is a combination of global carbon pricing and regulation.
• Without government action, sustainable investing can encourage energy
efficiency and improve carbon efficiency. But better data is needed.
• Advocacy, Transparency, Legal and Political actions can further impact
carbon efficiency.
• Much of the cost of adaptation will be borne by local, regional or federal
governments and these liabilities may force action.
• Technology may be the most important solution and it must be encouraged.