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Climate Change in Bolivia
- Expect Surprises
By Lykke E. Andersen*,
La Paz,
14
April
2008.
Climate change has suddenly become a hot
research topic in Bolivia (1). The
glaciers in the highlands
are melting, the lowlands are
flooded, and the government has
declared a state of national emergency due to natural disasters.
It is a good time to ask how climate change might be affecting
the poor Bolivians.
But first let's check exactly what climate
changes we are talking about.
The National Meteorological Service (www.senamhi.gov.bo)
provides useful data for 33 different
stations across Bolivia. They provide daily minimum and
maximum temperatures since 1/1/2004 until yesterday, as well as
historical monthly averages for the 1961-1990 period, which can
be used for comparison. It is therefore relatively simple to
calculate daily temperature anomalies for different parts of
Bolivia.
The results of
such an exercise might surprise you.
Of the 33
Bolivian weather stations, 7 experienced significant warming, 6
experienced no significant change, and 20 experienced
significant cooling. Most of the cooling took place in the
highlands (-1.5 degrees Celsius in Charaña, -1.2 in Oruro, -0.5
in Potosí, and -0.3 in El Alto, for example), while the lowlands
experienced much more modest changes (about
-0.2 degrees in most
places).
Central La Paz
is an atypical place by Bolivian standards, with warming of
about 1.4 degrees Celsium in the recent 4-5 years compared to
the average for 1961-1990. One might suspect the urban heat
effect to be playing a role here, as La Paz is
full of concrete and has
little vegetation to soften the effect. If any of the readers
know exactly where the Central La Paz station is located,
I would like to take a look at it.
Some people
might be sceptical of these "cooling" results and suggest that
the SENAMHI data are bad. Certainly, there are a lot of missing
observations. The person responsible for recording temperatures
at Potosí airport, for example, doesn't work weekends, so two-seventh
of the observations are missing. Other stations didn't start
recording until 2006.
If we limit
ourselves to the 17 stations with most complete data (at least
1100 daily observations since 1/1/2004), we find that 3 stations experienced
significant warming, 2 experienced no change, and 12 experienced
significant cooling. So, pretty much the same pattern.
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If you don't
trust Bolivian data at all, there are also some international
data available. The longest series, I could find, is for El Alto
for the 1/1/1995 - 31/3/2008 period, with a reference period of
1918-1989.
Figure 1 shows
the daily anomalies calculated from this international data
(see source below the graph). The
average anomaly is -2.0 degrees Celsius, suggesting that El Alto
is now substantially colder than it was during most of the
previous century.
The international data thus shows even more
cooling than the national data (-0.3 degrees for El Alto). This
may have to do with the longer reference period, as the
1961-1990 period used by SENAMHI (and most of the IPCC work) was
a relatively cold period. Indeed, in the 60s and 70s the media
was making a big fuss about the World being on the brink of a
new ice-age, because global temperatures were dropping and
glaciers advancing almost everywhere (2).
Figure 1: La Paz (El Alto): Average Daily Temperature Anomaly
1/1/1995 – 12/3/2008, compared to average monthly temperatures
for 1918-1989.
Sources:
For daily temperatures: Average Daily Temperature Archive,
University of Dayton, GSOD weather station no. 852010, located
at 16.51667S/68.18333W, 4014 meters above sea level. For
1918-1989 average monthly temperatures: The Global Historical
Climatology Network, El Alto station located approximately at
16.50S/68.20W, 4103 meters above sea level (http://www.worldclimate.com/cgi-bin/data.pl?ref=S16W068+1202+0010853G2).
Note:
Notice that the station for the historical data station
apparently is located a 89 meters higher than the current
station, implying that the historical data should be about half
a degree colder than the current data. The average anomaly may
therefore be biased towards zero by about half a degree Celcius.
So, if
you would like to study the impacts of climate change in Bolivia (and
thus receive some of the benefits), be sure at least to get the
direction of change right.
(*) Director, Institute for Advanced Development Studies, La
Paz, Bolivia. The author happily receives comments at the
following e-mail:
landersen@inesad.edu.bo.
(1)
For
those interested, UNDP in Bolivia has a call for proposals on
the Impacts of Climate Change on the Bolivian Economy.
The deadline is the 21st of April, 2008.
(2)
See, for
example, the 1975 Newsweek article "The
Cooling World".
Ó
Institute for Advanced Development Studies 2006.
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