English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Following the mid-Pleistocene transition, the dominant period of glacialcycles changed from 40 ka to ~100 ka. It is broadly accepted that the 40 kaglacial cycles were driven by cyclical changes in obliquity. However, thisforcing does not explain the ~100 ka glacial cycles. Mechanisms have beenproposed for ~100 ka cycles, but none are universally accepted. Any proposedmechanism for ~100 ka glacial cycles must give the Earth's climate system amemory of tens-of-thousands-of-years. This timescale is difficult to achievefor surface processes, however it is possible for the solid Earth. Recent worksuggests volcanic CO2 emissions change in response to glacial cycles and thatthere could be a ~50 ka delay in that response. Such a lagged response coulddrive glacial cycles from 40 ka cycles to an integer multiple of the forcingperiod. Under what conditions could the climate system admit such a response?We investigate this using a reduced-complexity model to establish the thresholdvolcanic variations required to induce 100 ka glacial cycles. This threshold iscompared to the probable range of volcanic activity over glacial cycles. Ourmodel is composed of three component models for energy balance, ice sheetgrowth and atmospheric CO2. The model is driven by insolation alone, with othercomponents varying according to a system of coupled, differential equations.The model replicates modern climate conditions and seasonality, CO2-doublingexperiments, and - when forced with ice core CO2 - the late-Pleistocene sealevel record. We obtain a switch from 40 ka to ~100 ka cycles as the mid-oceanridge CO2 response to glacial cycles is increased. These ~100 ka cycles arephase-locked to obliquity, lasting 80 or 120 ka. The mid-ocean ridge responserequired is, at best, just within a 95% confidence interval of MOR CO2emissions.

Modelling Coupled Oscillations of Volcanic CO2 Emissions and Glacial Cycles