[escepticos] Cambio climatico

[Francisco Colomer <f.colomer@xxxxxx>]

Hoy los medios se hacen eco de un estudio inglÃs sobre el cambio climÃtico, 
con el titular  "El deshielo polar puede anegar Londres y otras ciudades 
britÃnicas". El autor, Bill McGuire, del Benfield Hazard Research Centre, 
indica que al ritmo que se estÃn derritiendo los hielos antÃrticos, el nivel 
medio del mar podrÃa subir hasta 86 cm en 2080, y 6 metros al final del 
milenio.

Todo el estudio en (3,7 Mb):

http://www.benfieldhrc.org/activities/tech_papers/climate_change.pdf

Copio las conclusiones del estudio:

Executive Summary
- Atmospheric carbon dioxide concentrations have risen more in the last three
decades than in the previous three centuries. The rate of increase itself is 
also on the rise. During the 1980s and 1990s, concentration of atmospheric 
carbon dioxide rose by an average of 1.5 ppm a year. In both 2002 and 2003,
however, the level has risen by 2.5 ppm.
- The Kyoto Protocol requires that greenhouse gas emissions are reduced to 5.2
percent below 1990 levels within the 2008 â 2012 period. In actual fact they
have already risen by 10 percent.
- The 15 hottest years on record have occurred since 1980, the 10 hottest 
since 1990 and the five hottest since 1997.
- The Earth is hotter now than at any time in the last 2,000 years.
- During the 20th century, a veil of soot, smoke and particulate matter may 
have provided a shield against three quarters of the effects of global 
warming. With the atmosphere growing cleaner, the worst case temperature rise 
by 2100 may be 7 â 10 degrees Celsius.
- Even taking global warming into account, last yearâs European heat wave was
an event that should only happen every 46,000 years.
- A worst case 8 degrees C temperature rise by 2100 would result in wholesale
melting of the Greenland Ice Sheet and a rise in sea level of 6 m by the end 
of the millennium.
- In the UK, summers may be 50 percent or more drier and winters up to 30
percent wetter by 2080.
- In the south east of the UK, sea levels are expected to rise by between 26 
and 86 cm by the 2080s.
-  Annual economic damage due to UK flooding could increase from Â1 billion
now to between Â1.5 and Â21 billion by the 2080s, depending on the scenario.
- In the last 50 years the number of severe winter storms affecting the UK has
risen significantly.
- Global warming may lead to the formation of more tropical cyclones in the
South Atlantic.
- Independent studies point to significant contemporary changes in the
behaviour of North Atlantic ocean currents; perhaps heralding a weakening of
the Gulf Stream.

(Nota: llama especialmente la atenciÃn el punto 5, si lo he entendido bien, 
que la mayor poluciÃn en la atmÃsfera nos ha "protegido" de la entrada de 
rayos solares -ellos lo llaman "efecto sombrilla"- y que tener en el futuro 
una atmÃsfera mÃs limpia producirÃa un aumento de hasta 10 grados en la 
temperatura en 2100).

Hay tambiÃn quien piensa que el calentamiento global o la glaciaciÃn es un 
escenario posible, que ya ha ocurrido antes, y que no son consecuencia de la 
acciÃn humana. Solo que ahora nos afectarÃan mÃs, debido a nuestro modo de 
vida (en ciudades muy tecnificadas, sin acceso directo a recursos, etc). 

Que opinais? Realmente somos capaces de destruir las condiciones de vida en el 
planeta a corto plazo? Se mide una concentraciÃn mÃs alta de CO2 y mayores 
temperaturas, pero estÃn realmente relacionadas como causa-consecuencia?

Saludos,

	Paco


PD: Habies visto la pelÃcula "El dia despuÃs"? En ella la catÃstrofe ocurre al 
detenerse la corriente del golfo. Resulta estremecedoramente realista... (por 
cierto comienza con un cientÃfico explicando este tipo de cosas, y nadie le 
hace caso).