Science Source
The impact of natural and anthropogenic forcings on climate and hydrology since 1550
- Runs a climate simulation of an ocean/atmosphere general circulation model driven with natural forcings alone (constant “pre-industrial” land-cover and well-mixed greenhouse gases, changing orbital, solar and volcanic forcing) from 1492 to 2000
- Also carries out another simulation driven with natural and anthropogenic forcings (changes in greenhouse gases, ozone, the direct and first indirect effect of anthropogenic sulphate aerosol and land-cover) from 1750 to 2000
- These simulations suggest that since 1550, in the absence of anthropogenic forcings, climate would have warmed by about 0.1 K
- Compares a simulation driven by anthropogenic and natural forcings with a natural-only simulation, which suggests that anthropogenic forcings have had a significant impact on, particularly tropical, climate since the early nineteenth century
- Finds that both the hydrological cycle and cryosphere are also affected by anthropogenic forcings
- Finds that changes in tree-cover appear to be responsible for some of the local and hydrological changes as well as an increase in northern hemisphere spring snow cover
