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Los Estados Unidos de América. Presupuesto de carbono: contribuciones del cambio en el uso de la tierra
1Woods Hole Research Center, Post Office Box 296, Woods Hole, MA 02543, USA.
Science (New York, N.Y.)
|July 27, 1999
Resumen
Los cambios en el uso de la tierra en los Estados Unidos liberaron carbono significativo antes de 1945, pero secuestraron carbono después debido a la regeneración de los bosques. Las prácticas de gestión de la tierra influyeron en las emisiones de carbono de los Estados Unidos, compensando la producción de combustibles fósiles.
Área de la Ciencia:
- Ciencias ambientales Ciencias ambientales.
- Ecología Ecología Ecología.
- Ciencias del clima Ciencias del clima Ciencias del clima
Sus antecedentes:
- El uso histórico de la tierra, incluida la limpieza, el abandono y la recolección de madera, tiene un impacto significativo en el almacenamiento de carbono terrestre.
- Comprender estas dinámicas históricas de uso de la tierra es crucial para el modelado preciso del ciclo del carbono.
Objetivo del estudio:
- Para reconstruir los cambios históricos en el uso de la tierra en los Estados Unidos desde 1700 hasta 1990.
- Cuantificar el flujo neto de carbono hacia y desde los ecosistemas terrestres como resultado de estos cambios en el uso de la tierra.
Principales métodos:
- Reconstrucción de las tasas históricas de uso de la tierra (limpieza, abandono, cosecha, quema) utilizando los datos disponibles.
- Aplicación de un modelo de carbono terrestre para simular cambios anuales en el almacenamiento de carbono del ecosistema.
Principales resultados:
- Los cambios en el uso de la tierra liberaron un estimado de 27 +/- 6 petagramas de carbono (PgC) a la atmósfera antes de 1945.
- Después de 1945, los ecosistemas terrestres acumularon 2 +/- 2 PgC, principalmente debido a la supresión de incendios y la forestación de tierras agrícolas abandonadas.
- En la década de 1980, los flujos de carbono de la gestión de la tierra compensaron el 10-30% de las emisiones de carbono de los combustibles fósiles de Estados Unidos.
Conclusiones:
- El uso histórico de la tierra ha sido un importante impulsor del carbono atmosférico en los últimos tres siglos.
- El manejo moderno de la tierra, particularmente la supresión de incendios y el crecimiento forestal, ha cambiado el ecosistema terrestre de los Estados Unidos de una fuente neta de carbono a un sumidero.
- La gestión de la tierra juega un papel importante en la modulación de los presupuestos nacionales de carbono y los esfuerzos de mitigación del cambio climático.
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