Author: Marina

Marine heatwaves exacerbate climate change impacts for fisheries in the northeast Pacific

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Cheung, W. W. L., & Frölicher, T. L. (2020). Marine heatwaves exacerbate climate change impacts for fisheries in the northeast Pacific. Scientific Reports, 10 (1), 6678. https://doi.org/10.1038/s41598-020-63650-z

Summary:

Marine heatwaves (MHWs) have occurred in all ocean basins with severe negative impacts on coastal and ocean ecosystems. The northeast Pacific 2013–2015 MHW received major societal concerns. Yet, the knowledge about how MHWs impact fish stocks is limited. The authors of this study combined various model outputs to simulate responses of major northeast Pacific fish stocks to MHWs and showed that MHWs cause biomass decrease and shifts in biogeography of fish stocks with projected a doubling of impact levels by 2050 amongst the most important fisheries species over previous assessments. The authors stress the additional challenges from MHWs for fisheries and their management under climate change.

Policy relevant message:

Marine Heat Waves have occurred in all ocean basins with severe negative impacts on coastal and ocean ecosystems. They cause biomass decrease and shifts in biogeography of fish stocks with projected a doubling of impact levels by 2050 amongst the most important fisheries species over previous assessments.

Is deoxygenation detectable before warming in the thermocline?

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Hameau, A., Frölicher, T. L., Mignot, J., & Joos, F. (2020). Is deoxygenation detectable before warming in the thermocline? Biogeosciences, 17 (7), 1877–1895. https://doi.org/10.5194/bg-17-1877-2020

Summary:

Anthropogenic greenhouse gas emissions cause ocean warming and oxygen depletion, with adverse impacts on marine organisms and ecosystems. Warming is one of the main indicators of anthropogenic climate change, but thermocline1, changes in oxygen and other biogeochemical tracers may be a result of natural variability prior to warming. In about a third (35±11 %) of the global thermocline deoxygenation emerges prior to warming. In these regions, both reduced ventilation and reduced solubility add to the oxygen decline. In addition, reduced ventilation slows the propagation of anthropogenic warming from the surface into the ocean interior, further contributing to the delayed emergence of warming compared to deoxygenation. This study underlines the importance of an ocean biogeochemical observing system and that the detection of anthropogenic impacts becomes more likely when using multi-tracer observations.

1Thermocline: a sudden temperature change in water column, distinct from temperature of a layer above and below.

COMFORT at the Sustainable Development Goals event in Bergen!

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“Our common future ocean in a changing climate” joint session of the H2020 projects COMFORT and TRIATLAS coordinated by UiB formed part of the Day Zero event of the Sustainable Development Goals (SDGs) conference. The aim of the session was to provide fundamental knowledge on how to achieve SDG14 Life under water and SDG13 Climate action through international partnership of 57 institutes from 21 countries and to discuss how we, as scientists as society, can work together to achieve the SDGs. The session attracted a broad audience with a great number of students, non-scientists and non-specialists from outside of academia.

The event consisted of three major parts:

1) Two presentations: “Ocean under climate change” by Christoph Heinze focusing on the ocean acidification, warming and de-oxygenation and “Forecasting the ocean from temperature to fish” by Filippa Fransner focusing on climate predictions.

2) Enthusiastically received interactive quiz/poll with questions such as “What fraction of human-made carbon dioxide emissions does the ocean take up each year?” or “Why is climate prediction possible?”

3) Audience engaging panel discussion consisting of the Bjerkenss Centre for Climate Research experts: Are Olsen (moderator, UiB), Morten Skogen (IMR), Helene Langehaug (NERSC), Filippa Franser (UiB), Christoph Heinze (UiB) covered questions such as: “The SDGs are aimed to be achieved within the end of this decade. This is the time horizon of climate prediction models. Can they help to show us whether we are on the right track to achieve the SDGs?” or “We have the knowledge, and we have a global framework with quantified goals, nevertheless, in effect, nothing has been done. CO2 emissions are still rising. Why does the change take so much time?”

Christoph Heinze presenting at the Day Zero event

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