My Google Scholar profile can be found here. Below is a list of my highlighted research in progress, journal publications, publications in edited volumes, and some of the discussion papers and work in progress.
Highlighted Research in Progress
|"Econometric Modelling of Climate Systems: The Equivalence of Energy Balance Models and Cointegrated Vector Autoregressions" [download]. Revise and Resubmit at the Journal of Econometrics
Short Abstract: Estimates of both the human impact on climate as well as the economic impacts of climate change are crucial to inform policy decisions. Econometric modelling allows us to quantify these impacts and their uncertainties, but models have to be consistent with the underlying physics and the time series properties of the data. Here, I show that energy-balance models of climate are equivalent to an econometric cointegrated system and can be estimated in discrete time. This equivalence provides a basis for the use of cointegration methods to estimate climate responses and test their feedback. Further, it is possible to use the estimated parameters to quantify uncertainties in integrated assessment models of the economic impacts of climate change. In an application I estimate a system of temperatures, ocean heat content, and radiative forcing including greenhouse gases and find statistical support for the cointegrated energy balance model. Accounting for structural breaks from volcanic eruptions highlights large parameter uncertainties and shows that previous empirical estimates of the temperature response to increased CO2 concentrations may be misleadingly low due to model-misspecification.
|"Local Emissions Affect Local Climate: Attribution, Impacts and Policy" with Robert K. Kaufmann and Sucharita Gopal. [Under Review. Available on email request]
Short Abstract: To date, most empirical studies of the impacts of climate change assume that temperatures are strictly exogenous to (unaffected by) local economic activity, as the climate effects of most radiatively-active gases (e.g. CO2) are well mixed in the atmosphere. Here we test the hypothesis that local forcings from local emissions measurably affect local temperatures beyond global forcings by estimating a spatially-explicit dynamic econometric energy balance model from a 5-degree gridded panel which includes observations for global radiative forcing, temperatures, and proxies for local forcing. Results indicate that local emissions have explanatory power about local temperatures that extends beyond global radiative forcing. These results suggest that temperatures are not strictly exogenous for local economic activity, and also show that policy to slow climate change can generate local effects which changes the attractiveness of climate change policy.
|"Testing the Presence of Outliers to Assess Misspecification in Regression Models" with Xiyu Jiao. [Working Paper]
Short Abstract: The presence of outlying observations in a regression model can be indicative of model misspecification, consequently it is important to check for outlier contamination. However, algorithms used to detect outliers have a positive probability to find outliers even when, in fact, the data generation process has no outliers. Deriving distributional results on the expected retention rate of falsely discovered outliers, we propose two set of tests for the overall presence of outliers: first, tests on whether the observed proportion and number of detected outliers deviate from their expected values. Second, `scaling' tests on whether the number of detected outliers decreases proportionally with the level of significance used to detect outliers. We derive the asymptotic distribution of the tests based on iterated 1-step Huber-skip M-estimators. The tests are valid for stationary as well as (stochastically) trending regressors and have power against the number as well as magnitude of outliers. In applications of the tests we consider a cross-sectional macroeconomic model of economic growth, and re-visit a set of previous studies using indicator saturation. The tests can readily be implemented in the R-package ‘gets’.
|"Uncertain impacts on economic growth when stabilizing global temperatures at 1.5°C or 2°C warming"
with Moritz Schwarz, Kevin Tang, Karsten Haustein, and Myles R Allen, 2018.
Philosophical Transactions of the Royal Society A. DOI 10.1098/rsta.2016.0460.
Paper summary and projection data available here.
British Academy News Release here.
|"Automated General-to-Specific (GETS) Regression Modeling and Indicator Saturation for Outliers and Structural Breaks"
with James Reade and Genaro Sucarrat, 2018.
Journal of Statistical Software, 86(3). doi: 10.18637/jss.v086.i03
R-package 'gets' available on CRAN, with online demonstration here.
|"Spatial heterogeneity of climate change as an experiential basis for skepticism"
with Robert K. Kaufmann, Michael L. Mann, Sucharita Gopal, Jackie A. Liederman, Peter D. Howe, Xiaojing Tang, and Michelle Gilmore, 2017, Proceedings of the National Academy of Sciences, 114(1), doi: 10.1073/pnas.1607032113
Oxford Martin School news on the study: here, additional media coverage: here.
|"Carbon Dioxide Emission-Intensity in Climate Projections: Comparing the Observational Record to Socio-Economic Scenarios"
with Max Roser 2017, Energy, 3, 718-725, doi: 10.1016/j.energy.2017.06.119
Working paper version also available as Oxford Economics Discussion Paper, 810, here.
Oxford University Science Blog on the paper: here.
|"A new archive of large volcanic events over the past millennium derived from reconstructed summer temperatures"
with Lea Schneider, Jason Smerdon, Claudia Hartl-Meier, and Jan Esper, 2017. Environmental Research Letters. doi:10.1088/1748-9326/aa7a1b.
Oxford Martin School news on the paper.
|"Detecting Volcanic Eruptions in Temperature Reconstructions by Designed Break-Indicator Saturation"
with Lea Schneider, Jason E. Smerdon, and David F. Hendry (2016), Journal of Economic Surveys. doi: 10.1111/joes.12148
Working paper version available here. Columbia University article on the paper: here.
|"Detecting Location Shifts during Model Selection by Step-Indicator Saturation"
with David F. Hendry, Jurgen A. Doornik, and Jennifer L. Castle, 2015, Econometrics, 3, 240-264, doi:10.3390/econometrics03020240.
Code for indicator saturation: isat in gets (in R), and SIS in Ox.
|"Testing Competing Models of the Temperature Hiatus: Assessing the effects of conditioning variables and temporal uncertainties through sample-wide break detection"
with Michael L. Mann and Robert K. Kaufmann, 2015, Climatic Change, 131:4, 705-718, doi: 10.1007/s10584-015-1391-5.
Working paper version available here.
|"Climate Science: Breaks in Trends"
with Myles R. Allen, 2013, Nature Geoscience, 6, 992-993, doi:10.1038/ngeo2015.
Media coverage: here.
|"Some hazards in econometric modelling of climate change"
with David F. Hendry, 2013, Earth System Dynamics, 4, 375-384, doi:10.5194/esd-4-375-2013.
Publications in Edited Volumes
|"All Change! The Implications of Non-stationarity for Empirical Modelling, Forecasting and Policy"
with David F. Hendry (2016), Oxford Martin Policy Paper, (peer-reviewed).
Available online here.
Oxford Martin School article on the paper: here.
|"Anthropogenic Influences on Atmospheric CO2"
with David F. Hendry, 2013, Handbook on Energy and Climate Change. Ch. 12. R. Fouquet ed. Edward Elgar. Available online here.
Discussion Papers and Further Papers in Progress (please email for availability)
|"Exogeneity in Climate Econometrics"
2017, Oxford Department of Economics Working Paper. Available online here.
|"Testing for time-varying predictive accuracy using bias-corrected indicator saturation"
Oxford Economics Working Paper [Available upon email request]
Code to implement the test: isattest function in the latest version of our R package gets
|"Are we running out of resources?"
with Cameron Hepburn, Alex Teytelboym, and Alexander Pfeiffer
|"Assessing poolability, stability over time, and the presence of outliers in fixed-effects panel regressions using indicator saturation"
With J. Reade and G. Sucarrat.
With J. A. Doornik and D.F. Hendry.
|"Quantifying the Uncertainty around Break Dates in Models using Indicator Saturation"
With D. F. Hendry. [Available on email request]
|"Step Indicator Saturation"
with David F. Hendry and Jurgen A. Doornik, 2013, Oxford Economics Discussion Paper, 658.
New version published as "Detecting Location Shifts during Model Selection by Step-Indicator Saturation", 2015, Econometrics, 3, 240-264. Available online here.