Weekend science reading recommendations

Changes in the environment have often had decisive geopolitical effects, such as the crop failures of the Little Ice Age weakening Scotland so that it was merged into the United Kingdom (as the climate warms, so does the Scottish Scottish independence. 

This list of weekend reading recommendations links to articles from three different fields, all important.  Excerpts appear below.

1. “Correlation between Cosmic Rays and Ozone Depletion“, Q.-B Lu, Department of Physics and Astronomy, U of Waterloo), Physical Review Letters, 20 March 2009 
2. “Global hurricane activity reaches new lows“, Ryan N. Maue, Climate Audit, 12 March 2009 — To the lowest level in 30 years.
3. “Rust in the Food Supply“, Popular Science, 31 March 2009 — A threat to wheat is a threat to the world. This discusses the Ug99 strain of the killer wheat fungus (stem rust), last mentioned here.  For more on this see the FM reference page Articles About the Global Food Crisis.

Comments will be turned on upon my return, hopefully sometime today.

 Excerpts

(1)  “Correlation between Cosmic Rays and Ozone Depletion“, Q.-B Lu, Department of Physics and Astronomy, U of Waterloo), Physical Review Letters, 20 March 2009 — Abstract:

This Letter reports reliable satellite data in the period of 1980-2007 covering two full 11-yr cosmic ray (CR) cycles, clearly showing the correlation between cosmic rays (CR) and ozone depletion, especially the polar ozone loss (hole) over Antarctica. The results provide strong evidence of the physical mechanism that the CR-driven electron-induced reaction of halogenated molecules plays the dominant role in causing the ozone hole. Moreover, this mechanism predicts one of the severest ozone losses in 2008-2009 and probably another large hole around 2019-2020, according to the 11-yr CR cycle.

(2)  “Rust in the Food Supply“, Popular Science, 31 March 2009 — A threat to wheat is a threat to the world. This discusses the Ug99 strain of the killer wheat fungus (stem rust), last mentioned here.  For more on this see the FM reference page Articles About the Global Food Crisis.  Excerpt:

Food-borne illness frequently grabs headlines: tomatoes, peanut butter and, most recently, pistachios have all made people sick from salmonella and caused headaches for grocers across the United States.

Now, another food illness of sorts is popping up on the international radar screen — only this one makes the food itself ill. Well, one of the plants that turns into much of our food, in any case. Scientists from 40 countries on six continents are fighting a virulent form of an old wheat disease that some fear could threaten 90 percent of the world’s wheat crop. They aim to fight the fungus on the genetic level, hoping to prevent it from spreading to North America by replacing much of the world’s wheat varieties with tougher plants.

At a conference in Mexico earlier this month, scientists confirmed that a newly emerged wheat rust strain known as Ug99 is now in most of eastern Africa and is marching toward South Asia, a region that produces 19 percent of the world’s wheat. The wind-borne fungus has already devastated farms in Kenya, where some farmers have reported losses up to 80%.

… Though the fungus is isolated — for now — to east Africa, the Middle East, and South Asia, most American wheat varieties are susceptible. The U.S. Department of Agriculture’s Agricultural Research Service says plants grown on 75 percent of U.S. winter wheat acreage are vulnerable, including varieties grown throughout the West and Midwest. About 4 million acres of barley in the Midwest are also threatened.

(3)  “Global hurricane activity reaches new lows“, Ryan N. Maue, Climate Audit, 12 March 2009 — Maue is studying for his PhD at the Center for Ocean-Atmospheric Studies at Florida State University (COAPS).  See his bio here, listing his publications. Excerpt

As previously reported here and here at Climate Audit, and chronicled at my Florida State Global Hurricane Update page, both Northern Hemisphere and overall Global hurricane activity has continued to sink to levels not seen since the 1970s. Even more astounding, when the Southern Hemisphere hurricane data is analyzed to create a global value, we see that Global Hurricane Energy has sunk to 30-year lows, at the least. Since hurricane intensity and detection data is problematic as one goes back in time, when reporting and observing practices were different than today, it is possible that we underestimated global hurricane energy during the 1970s. (See notes at bottom to avoid terminology discombobulation.)

Using a well-accepted metric called the Accumulated Cyclone Energy index or ACE for short (Bell and Chelliah 2006), which has been used by Klotzbach (2006) and Emanuel (2005) (PDI is analogous to ACE), and most recently by myself in Maue (2009), simple analysis shows that 24-month running sums of global ACE or hurricane energy have plummeted to levels not seen in 30 years. Why use 24-month running sums instead of simply yearly values? Since a primary driver of the Earth’s climate from year to year is the El Nino Southern Oscillation (ENSO) acts on time scales on the order of 2-7 years, and the fact that the bulk of the Southern Hemisphere hurricane season occurs from October – March, a reasonable interpretation of global hurricane activity requires a better metric than simply calendar year totals. The 24-month running sums is analogous to the idea of “what have you done for me lately”.

Why the record low ACE?

During the past 2 years +, the Earth’s climate has cooled under the effects of a dramatic La Nina episode. The Pacific Ocean basin typically sees much weaker hurricanes that indeed have shorter lifecycles and therefore — less ACE . Conversely, due to well-researched upper-atmospheric flow (e.g. vertical shear) configurations favorable to Atlantic hurricane development and intensification, La Nina falls tend to favor very active seasons in the Atlantic (word of warning for 2009). This offsetting relationship, high in the Atlantic and low in the Pacific, is a topic of discussion in my GRL paper, which will be a separate topic in a future posting. Thus, the Western North Pacific (typhoons) tropical activity was well below normal in 2007 and 2008 (see table). Same for the Eastern North Pacific.

The Southern Hemisphere, which includes the southern Indian Ocean from the coast of Mozambique across Madagascar to the coast of Australia, into the South Pacific and Coral Sea, saw below normal activity as well in 2008. Through March 12, 2009, the Southern Hemisphere ACE is about half of what’s expected in a normal year, with a multitude of very weak, short-lived hurricanes.

All of these numbers tell a very simple story: just as there are active periods of hurricane activity around the globe, there are inactive periods, and we are currently experiencing one of the most impressive inactive periods, now for almost 3 years.

Bottom Line

Under global warming scenarios, hurricane intensity is expected to increase (on the order of a few percent), but MANY questions remain as to how much, where, and when. This science is very far from settled. Indeed, Al Gore has dropped the related slide in his PowerPoint.

Many papers have suggested that these changes are already occurring especially in the strongest of hurricanes, e.g. this and that and here, due to warming sea-surface temperatures (the methodology and data issues with each of these papers has been discussed here at CA, and will be even more in the coming months).

The notion that the overall global hurricane energy or ACE has collapsed does not contradict the above papers but provides an additional, perhaps less publicized piece of the puzzle. Indeed, the very strong interannual variability of global hurricane ACE (energy) highly correlated to ENSO, suggests that the role of tropical cyclones in climate is modulated very strongly by the big movers and shakers in large-scale, global climate. The perceptible (and perhaps measurable) impact of global warming on hurricanes in today’s climate is arguably a pittance compared to the reorganization and modulation of hurricane formation locations and preferred tracks/intensification corridors dominated by ENSO (and other natural climate factors). Moreover, our understanding of the complicated role of hurricanes with and role in climate is nebulous to be charitable.

We must increase our understanding of the current climate’s hurricane activity.

Afterword

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For more information

To read other articles about these things, see the FM reference page on the right side menu bar.  Of esp relevance to this topic:

• Food – articles about this global crisis
• About Science & Nature – my articles
• About Science & nature – studies & reports – note section 6, drivers of Earth’s climate
• About Science & Nature – general media articles
• About Science & Nature – the history of climate fears