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Category — Temperature trends

Earth Day 2012: Top 10 Positive Climate Developments

The scientific findings of the human influence on the climate system have been, and perhaps will always be, a mixed bag. Assuming strong positive feedback effects, and thus a high climate sensitivity, it certainly can be argued that the bad outweighs the good. But if feedback effects are more neutral, the sign of the externality flips from negative to positive given that, on net, a moderately warmer, wetter, and CO2-fertilized world is quite arguably a better one.

Earth Day 2012 yesterday brought forth predictable cries of doom-and-gloom. But there are plenty of positives on closer inspection on the climate front, developments which have undoubtedly spilled over into making the earth a better place for humanity at large.

Here is my Top 10 list of positive climate developments based on the recent empirical data and the latest scientific literature:

10) The growing season across the Northern Hemisphere is expanding; [Read more →]

April 23, 2012   45 Comments

2011 U.S. Temperature Update: Alarmism Not

The first six months of 2011 are now in the books. Heat waves are currently in the headlines, but how does the national average temperature compare to other years and ‘normal’? And what does the first half of the year portend for the year as a whole? 

The indication is that 2011 will mark the continued return of U.S. national temperatures to conditions much closer to the 20th century mean, down from the unusually elevated temperatures that characterized the 1998–2010 period.

If this proves to be the case, it strongly suggests that the unusually warm decade from 1998–2007, was just that–unusual–and does not best represent the expected trend or the climate state of the U.S. for the next several decades to come.

Background

The U.S. National Climatic Data Center has compiled a data set representing the annual average temperature for the contiguous United States which dates back to 1895.

Figure 1 shows that history, from the beginning through 1997. Over that time, there was really not much worth writing home about—there were signs of inter-decadal variability, but nothing that seemed to scream “dangerous anthropogenic global warming!” The overall upward trend was being driven more by cool conditions in the early decades of the record, rather than warm conditions at the end of the record. [Read more →]

July 25, 2011   10 Comments

A Cherry-Picker’s Guide to Temperature Trends Update: Warming Crisis Not

Back in October 2009, my post “A Cherry-Picker’s Guide to Temperature Trends” examined the many different statements that could be made to describe the tendencies of global temperatures over the past 20 years. I concluded that anything from rapid cooling to a faster than expected warming could be supported by carefully picking through the available data.

Now, more than a year later, and after one of the “warmest years on record,” I’ve updated my analysis so that any new statements characterizing global temperature can be evaluated against the complete set of recent observations.

In general, I find that statements such as “global warming has stopped” should be tempered, at least for the time being. But I conclude that my original article’s summary remains more or less* applicable:

What I can say for certain, is that the recent behavior of global temperatures demonstrates that global warming is occurring at a much slower rate than that projected by the ensemble of climate models, and that global warming is most definitely not accelerating.

I say “more or less” because one could argue from the data (as we’ll see below) that the warming rate during recent years has upticked with the warmth in 2010 indicating a warming that is occurring faster than projected and is accelerating. But, I think that this represents a temporary condition.

In due course (say over the next several months), the warmth in 2010 will continue to subside as the cooling influence from a Pacific La Niña event supplants the warming influence of last year’s El Niño (see here for example). This will have the effect of flattening out recent temperature trends and returning them once again to lower-than-projected values. I imagine that we’ll see such an impact when it comes time again for me to produce an update to this update.

But until that time, I’ll describe the situation as it presents itself data available through December 2010. [Read more →]

February 7, 2011   13 Comments