Thursday, September 19, 2013

On the 60% Larger Arctic Ice Cap Year-Over-Year and on the Recent Global Warming Hiatus

I am not an atmospheric scientist. But I thought I could introduce some explanations about the recent measurements that are seemingly contradictory to the IPCC reports (AR4 and upcoming AR5).

First, does this year's Arctic ice cap that is reportedly 60% larger than the last year's mean climate is cooling? Not so. It is just a symptom of the so-called 'regression toward the mean' bias.
Let's look at the measurement data. The 60% increase in 2013 is just due to the record-contraction of the Arctic ice cap in 2012 (Meier, 2012). The downward trend is still valid.

Source: National Snow & Ice Data Center.

Second, does the hiatus of global warming since 1998 mean that the IPCC's forecasts are outright wrong? Not so. Their models were found wrong in that they couldn't predict the anomaly (How much the models were wrong can be found at Fyfe et al., (2013)). However, the overall global warming is happening exactly as the IPCC has been telling the world.
A Nature paper published today (Kosaka & Xie, 2013) clarifies what is really happening on the Earth. If their analysis is correct (Their explanation corresponds to 97% of temperature changes during 1970-2012.), the former climate models underestimated the natural variation known as "La-NiƱa-like decadal cooling." Their conclusion is,
"Although similar decadal hiatus events may occur in the future, the multi-decadal warming trend is very likely to continue with greenhouse gas increase."
(The IPCC report use the term "very likely" when the probability of a predicted outcome is greater than 90%.)
I think this study is a good answer to the so-called confusion between the short-term noise and the long-term change.


Fyfe, J. C., Gillett, N. P., & Zwiers, F. W. (2013). Overestimated global warming over the past 20 years. Nature Climate Change, 3(9), 767-769. [Full-text at]

Kosaka, Y., & Xie, S.-P. (2013). Recent global-warming hiatus tied to equatorial Pacific surface cooling. Nature, 501, 403-407. [Full-text at] (If you don't have a permission to read this article, just open the following link.

Meier, W. (2012). Record Low Arctic Sea Ice Extent in 2012: An exclamation point on a long-term declining trend [PowerPoint slides]. Boulder, CO: National Snow & Ice Data Center. [Slides at]

Wednesday, September 18, 2013

Temporal Changes in the Spatial Distribution of Global CO2 Emissions, 1970-2008

Please watch in HD 720p (and in full-screen mode) for a clearer video.

Source: Emissions Database for Global Atmospheric Research (EDGAR;

Friday, September 13, 2013

Three Recent Reports on Water-Energy Nexus in the United States

Almost three years ago, I wrote a post about 'water consumption in electricity generation using different technologies' ( However, indeed, I didn't have to collect those data. Two very good papers on the topic had been published by researchers from the National Renewable Energy Laboratory.
(Paper 1: Macknick, J., Newmark, R., Heath, G., & Hallett, K. C. (2012). Operational water consumption and withdrawal factors for electricity generating technologies: a review of existing literature. Environmental Research Letters, 7(4), 045802. [Full-text at]
Paper 2: Meldrum, J., Nettles-Anderson, S., Heath, G., & Macknick, J. (2013). Life cycle water use for electricity generation: a review and harmonization of literature estimates. Environmental Research Letters, 8(1), 015031. [Full-text at])

Nowadays, the nexus between energy and water seems to have become an even more popular topic in the United States. Over the past two months, three notable U.S. institutions published lengthy reports on the issue. The reports are:

Rogers, J., Averyt, K., Clemmer, S., Davis, M., Flores-Lopez, F., Frumhoff, P., Kenney, D., Macknick, J., Madden, N., Meldrum, J., Overpeck, J., Sattler, S., Spanger-Siegfried, E., & Yates. D. (2013). Water-Smart Power: Strengthening the U.S. Electricity System in a Warming World. Cambridge, MA: Union of Concerned Scientists. [Full-text at]

Water in the West. (2013). Water and Energy Nexus: A Literature Review. Stanford, CA: Stanford Woods Institute for the Environment and the Bill Lane Center for the American West. [Full-text at]

Whited, M., Ackerman, F., & Jackson, S. (2013). Water Constraints on Energy Production: Altering our Current Collision Course. Newton, MA: Civil Society Institute. [Full-text at]