Interviews and Links on Climate Change

Scientific American carries interviews with Nicholas Stern, Bjorn Lomborg and Gary Yohe and also has some useful links on what else but ...........Climate Change.

Wheat, Apples and Chickenpox: From the Plain Wrong to the Ridiculous

A neighbour’s child has contracted chicken pox for a second time. This is in spite of being vaccinated. It must surely be very rare as both the vaccine and a prior case of chickenpox should have helped develop immunity. According to the doctor such cases are becoming quite frequent and the reasons are climate change, pollution and eating of junk food!!! (This is not a concocted story, trust me. It is easy to pick on the three great villains of our times).

Last year when the apple crop in Himachal Pradesh was poor, farmers, politicians and even scientists were quick to invoke climate change as the reason. That apple production has fluctuated for as long as one can remember was conveniently forgotten. And this year a bumper crop has lead to a scramble to hire scarce labour for harvesting the fruits – no mention of climate change.

This is what Dr Pachauri (of Nobel Prize fame) said sometime back:

“…………R.K. Pachauri, chairman of the IPCC, said: “Wheat production in India is already in decline, for no other reason than climate change. Everyone thought we didn’t have to worry about Indian agriculture for several decades. Now we know it’s being affected now…………..”

Again, more recently:

“…………..Climate change is bringing down wheat production in India, chairman of the Intergovernmental Panel on Climate Change (IPCC) Rajendra K. Pachauri said in Ahmedabad Monday……….

………..'Agriculture productivity, particularly of wheat, has shown signs of going down as a result of the climate change,' Pachauri told an international conference on environmental education at the Centre for Environment Education…………"

Intrigued, I decided to look at the evidence.

Here are the figures for the past decade and more.

Wheat	Area	Production	Yield
Units	mha	million tonnes	kgs/ha
1995-96	25.01	62.10	2483
1996-97	25.89	69.35	2679
1997-98	26.70	66.35	2485
1998-99	27.52	71.29	2590
1999-00	27.49	76.37	2778
2000-01	25.73	69.68	2708
2001-02	26.34	72.77	2762
2002-03	25.20	65.76	2610
2003-04	26.60	72.16	2713
2004-05	26.38	68.64	2602
2005-06	26.48	69.35	2619
2006-07	28.03	74.89	2671

Source: Extracted from 1 and 2. For 2006-07: the estimates are the 4^th advance estimates from 1. See also this.

I don’t see any decline in production. Yes, there were two down years recently - 2004-05 and 2005-06 but production has jumped in 2006-07. Further, such declines and recoveries are part of the cycle of agricultural production. (Look at the table and for more see the sources listed). Dr. Pachauri’s statement illustrates the pitfalls of jumping to conclusions using a year or two of agricultural data.

Production is stable or rising, albeit slowly but since area under cultivation can change looking at yields is perhaps far more useful. Again no discernable trend is visible.

It is also odd that one picks on one crop – wheat – to make a case for climate change affecting output. What about other crops? It is worth noting that during 2006-07 India has harvested record levels of total foodgrains (though not wheat, where the harvest is the second-best ever), sugarcane, cotton and soybean (see this). Production of rice, the other major crop has been stable to rising.

Is there something unique about wheat that would make it more vulnerable to a warmer earth? Wheat is a Rabi (winter) crop. But a perusal of the data for cereals, foodgrains and other crops for the Rabi season suggests no declining trend (data is not presented here but look at 1, 2 and 3).

In fact, it could be argued that higher concentration of carbon dioxide and higher temperatures should at least initially, boost yields, but we let that pass for the moment.

However, the assertion that wheat output is being adversely affected by climate change doesn’t withstand even preliminary scrutiny.

Climate change is a serious matter deserving of our utmost attention. But when lazy or ignorant minds - whether a doctor in India’s science city or the head of a Nobel Prize winning body of several hundred scientists - start jumping to conclusions it is obvious that the desire for the dramatic has taken precedence over the need to stick to the facts.

On Food that Flies

Tim Harford on the eat "local" idea.

Save Rhinos, Lose Antelopes?

A recent post by Alex Tabarrok refers to an old New Scientist story on a rhino rescue plan gone awry.

Help in Our Troubled Times

While carbon offsetting takes care of Climate Change here is a chance for you to neutralise your other sins!!!!