Volcanoes as agents of past environmental change

Abstract

In recent years a sequence of papers has discussed the impact of volcanic eruptions upon global environments. Emphasis has been placed upon their potential role in depressing hemispheric temperatures and affecting global weather patterns. Many researchers have related ecological, environmental and historical phenomena to individual eruptions. However, the linking of spatially and temporally disparate phenomenon to eruption chronologies involves several levels of supposition and at each level in the argument greater potential for error arises. This paper examines critically a number of important issues that arise from these studies. How valid are the linkages that are drawn? Do they establish a dependent relationship or merely coincidence? The validity of linking volcanic activity with disparate spatial and temporal events in the climatic, historical and palaeoecological records is addressed. There can be little doubt that volcanoes have a great effect on proximal climates and environments, but their global impact is less well understood. The scale and magnitude of responses to large eruptions such as the historically notorious Tambora_1815.and Mt. Pinatubo_1991.is far from consistent. This paper urges the adoption of a more critical perspective when considering these issues.

Evaluating the link between the sulfur-rich Laacher See volcanic eruption and the Younger Dryas climate anomaly

“…Once in the atmosphere, sulfate aerosols induce summer cooling by scattering incoming solar radiation back to space (Timmreck and Graf, 2006;Baldini et al, 2015a). An eruption's sulfur content, rather than its explosivity, determines most of the climate response (Robock and Mao, 1995;Sadler and Grattan, 1999). Furthermore, recent research has also highlighted the role of volcanogenic halogens, such as Cl, Br, and F, in depleting stratospheric ozone (Cadoux et al, 2015;Klobas et al, 2017;Kutterolf et al, 2013;Vidal et al, 2016;LeGrande et al, 2016).…”

Fossil leaves of Banksia, Banksieae and pretenders: resolving the fossil genus Banksieaephyllum

“…Volcanism provides a convenient mechanism for this increase but the explanation is under challenge (Sellwood et al 1994, Heller et al 1996, Cowling 1999, Sadler and Grattan 1999, Kump 2000. For example, high CO 2 concentrations could be due to a change in deepwater circulation, which in turn altered the flux of warm, saline water from low to high latitudes (MacLeod and Huber 1996).…”

Les effets géographiques des éruptions volcaniques

“…Cependant, le même mécanisme peut contre toute attente entraîner des récoltes plus abondantes que la normale : alors que la France et les Pays-Bas connaissaient des étés frais et très pluvieux en 1816 (Post, 1977 ;Sadler et Grattan, 1999), un an après l'éruption plinienne du Tambora en Indonésie, le Danemark eut un été plus chaud et plus sec qu'en temps normal, permettant une hausse des récoltes (Neumann, 1990). Il convient par conséquent d'éviter les généralisations.…”