Causes of climate change over the historical record

Hegerl, Gabriele C; Brönnimann, Stefan; Cowan, Tim; Friedman, Andrew R; Hawkins, Ed; Iles, Carley; Müller, Wolfgang; Schurer, Andrew; Undorf, Sabine (2019). Causes of climate change over the historical record. Environmental Research Letters, 14(12), p. 123006. IOP Publishing 10.1088/1748-9326/ab4557

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This review addresses the causes of observed climate variations across the industrial period, from 1750 to present. It focuses on long-term changes, both in response to external forcing and to climate variability in the ocean and atmosphere. A synthesis of results from attribution studies based on palaeoclimatic reconstructions covering the recent few centuries to the 20th century, and instrumental data shows how greenhouse gases began to cause warming since the beginning of industrialization, causing trends that are attributable to greenhouse gases by 1900 in proxy-based temperature reconstructions. Their influence increased over time, dominating recent trends. However, other forcings have caused substantial deviations from this emerging greenhouse warming trend: volcanic eruptions have caused strong cooling following a period of unusually heavy activity, such as in the early 19th century; or warming during periods of low activity, such as in the early-to-mid 20th century. Anthropogenic aerosol forcing most likely masked some global greenhouse warming over the 20th century, especially since the accelerated increase in sulphate aerosol emissions starting around 1950. Based on modelling and attribution studies, aerosol forcing has also influenced regional temperatures, caused long-term changes in monsoons and imprinted on Atlantic variability. Multi-decadal variations in atmospheric modes can also cause long-term climate variability, as apparent for the example of the North Atlantic Oscillation, and have influenced Atlantic ocean variability. Long-term precipitation changes are more difficult to attribute to external forcing due to spatial sparseness of data and noisiness of precipitation changes, but the observed pattern of precipitation response to warming from station data supports climate model simulated changes and with it, predictions. The long-term warming has also led to significant differences in daily variability as, for example, visible in long European station data. Extreme events over the historical record provide valuable samples of possible extreme events and their mechanisms.

Item Type:

Journal Article (Review Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Climatology
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geography
08 Faculty of Science > Institute of Geography > Physical Geography

Graduate School:

Graduate School of Climate Sciences

UniBE Contributor:

Brönnimann, Stefan

Subjects:

900 History > 910 Geography & travel

ISSN:

1748-9326

Publisher:

IOP Publishing

Funders:

[18] European Research Council
[UNSPECIFIED] NERC
[UNSPECIFIED] Wolfson Foundation

Language:

English

Submitter:

André Hürzeler

Date Deposited:

20 Jan 2020 09:15

Last Modified:

20 Jan 2020 09:15

Publisher DOI:

10.1088/1748-9326/ab4557

Uncontrolled Keywords:

climate change, instrumental record, attribution, extreme events, precipitation

BORIS DOI:

10.7892/boris.138214

URI:

https://boris.unibe.ch/id/eprint/138214

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