Are There Early Warning Signals of Tipping Points in Arctic Sea Ice?

by Emil Morhardt

Everyone agrees that it would be helpful in making climate policy if we had some advance warning of climate tipping points. Williamson et al. (2016) set out to look for one associated with the melting of the Arctic sea ice. They asked if there is any evidence that the sea ice is about to undergo a local tipping point (which they also refer to as a bifurcation) that would lead to much faster melting. In the case of Arctic sea ice, the annual melting is caused by the summer sun, and a long-term parameter change that is enhancing it is the gradual buildup of CO2 in the atmosphere. Melting is limited partially by the fact that much of the incoming solar radiation is reflected back to space by the ice. A tipping point might be reached when enough of the ice is melted that the amount of sunlight absorbed by the ice-free open ocean begins to warm it faster each cycle. Although this study did not find any evidence for an imminent tipping point the authors noted that the sort of signal they were looking for might not occur until very close to a tipping point. That would, of course, make it useless for long-term policymaking. Their approach to looking for a signal is interesting though, and could be applied to many other potential climate tipping points. Continue reading

Climatic Tipping Points and Optimal Fossil Fuel Use

by Emil Morhardt

Should we plan to decrease fossil fuel use as quickly as possible to decrease damage from global warming? Maybe not according to Gustav Engström and Johan Gars (2016), Swedish economists, who consider the possibility that planned reduction of fossil fuel use might cause suppliers of it to increase production now in advance of potential decreased value of it in the future.

Their focus is economically-important climatic tipping points—relatively sudden climatic changes triggered by gradual global warming—that could have drastic economic consequences; they are less concerned with environmental damage with low immediate economic consequences, and they argue that most economists have modelled the effects of climate change without taking climatic tipping points into consideration. These potential tipping points, however, might not exist, in which case, they argue, it would be best to proceed gradually with climate reforms, but develop a strategy to deal with any tipping points should they occur. Continue reading

Is (Was) Global Warming on Hold?

by Emil Morhardt

A glance at the graph above, from the University of East Anglia Climatic Research Unit (, shows that the last two time periods covered (encompassing 2015) are warmer than at any time since 1850. In the prior decade, however, there was much less upward trend, feeding speculation, particularly from climate-change deniers, that all of the warming we have seen since 1900 was largely unrelated to anthropogenic carbon dioxide emissions. There was also speculation from other scientists that the apparent slowdown in warming was statistically “in the noise” and that, in time, there would be a rebound and that the monotonic upward trend since the mid-1970s would soon resume, as it now seems to have. Time will tell, of course, but mainstream climate scientists Fyfe et al. (2016) have just made a new analysis of the early 2000s warming slowdown and pronounce it real and probably largely attributable to the early 2000s’ negative phase of the Interdecadal Pacific Oscillation (IPO) in which intensification of the trade winds lowered sea surface temperatures enough to offset the warming from the ongoing increases in atmospheric greenhouse gases.  Continue reading

Just Released! “Energy, Biology, Climate Change”

FrontCover6x9 white border 72dpi EBCC2015

Our newest book, published on May 6, 2015 and available at for $19.95.

The focus of this book is the interactions between energy, ecology, and climate change, as well as a few of the responses of humanity to these interactions. It is not a textbook, but a series of chapters discussing subtopics in which the authors were interested and wished to write about. The basic material is cutting-edge science; technical journal articles published within the last year, selected for their relevance and interest. Each author selected eight or so technical papers representing his or her view of the most interesting current research in the field, and wrote summaries of them in a journalistic style that is free of scientific jargon and understandable by lay readers. This is the sort of science writing that you might encounter in the New York Times, but concentrated in a way intended to give as broad an overview of the chapter topics as possible. None of this research will appear in textbooks for a few years, so there are not many ways that readers without access to a university library can get access to this information.

This book is intended be browsed—choose a chapter topic you like and read the individual sections in any order; each is intended to be largely stand-alone. Reading all of them will give you considerable insight into what climate scientists concerned with energy, ecology, and human effects are up to, and the challenges they face in understanding one of the most disruptive—if not very rapid—event in human history; anthropogenic climate change. The Table of Contents follows: Continue reading

Can Pacific Salmon Adapt to Climate Change?

by Emil Morhardt

Chinook (king) salmon deposit their eggs in the cobbles of Pacific Coast streambeds, where they, and the subsequent developing juveniles spend months before heading out to sea. Some of these streams can get quite warm by salmon standards, and more than one major run has been heavily depleted by temperatures higher than 24 °C which seems to be generally lethal to this species. As global warming progresses we can expect more salmon streams to reach this temperature, so an important question is whether these fish have either the developmental plasticity or the genetic variability that will allow them to adapt. Muñoz et al. (2015) crossbred 16 wild chinook salmon caught at Canada’s Quinsam River Hatchery so as to get 64 different genotypes, then reared half of them at the hatchery ambient water temperatures and the other half at temperatures 4 °C higher. They then looked to see if cardiac function, the apparent limiting factor in high temperature mortality, was shifted to higher temperatures. Continue reading

How Many Benefits Does Commercial Forestry Provide?

by Emil Morhardt

Forestry economists worry about whether foresters can claim more societal benefits, including offsetting the effects of climate change, from forestry than merely the increased supply of trees; in econ-speak, “…what change in human well-being results from increasing, reducing or qualitatively varying…” the supply of ecosystem services commercial forests provide? Colin Price (2014) addresses this question largely in the abstract by providing an overview of eight general approaches to valuing non-market effects, which, although they break little new ground, provide an extremely clear overview of a generally murky subject. Continue reading

American Evangelicals and Climate Policy

by Emil Morhardt

How strongly are American evangelicals—who comprise a quarter of the adult US population—opposed to doing anything about climate change? Chaudoin et al. (2013), begin by citing previous research showing that many evangelicals are particularly resistant to any policies that would “…endanger the divine covenant on which the United States was built” and that might lead somehow to a single world government. Hence, the whole idea of an organization like the Intergovernmental Panel on Climate Change (IPCC), run under the auspices of the United Nations, having any authority over actions of the United States would be anathema to them. This being the case, the authors thought perhaps that evangelicals would be more welcoming to domestic climate policy initiatives than to the US partaking in international ones, and it turned out that they were correct. Continue reading