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Environment Minister Tanya Plibersek has been taken to court over 11 threatened species. Here’s why

Biodiversity News - Tue, 04/03/2025 - 06:09

Thousands of Australian species and ecological communities are threatened – and many don’t have a recovery plan in place. Euan Ritchie, Professor in Wildlife Ecology and Conservation, School of Life & Environmental Sciences, Deakin University Licensed as Creative Commons – attribution, no derivatives.

Wed 19 Mar 14:00: Tipping points of the Ross and Filchner-Ronne Ice Shelves: how worried should we be?

Conservation-related talks - Wed, 26/02/2025 - 09:05

Tipping points of the Ross and Filchner-Ronne Ice Shelves: how worried should we be?

Ocean models consistently project that with sufficient climate change forcing, the Ross and Filchner-Ronne ice shelf cavities could abruptly transition from a cold state to a warm state. Crossing these tipping points would have profound consequences for basal melt rates, buttressing of ice streams, and ultimately sea level rise. Here we analyse over 14,000 years of “overshoot” simulations with the UK Earth System Model, which includes a fully coupled Antarctic Ice Sheet. As the climate warms, stabilises at different temperatures, and cools again, we simulate many examples of the cavities tipping and recovering. We find that global warming thresholds of around 3.5°C and 5°C tip the Ross and Filchner-Ronne respectively. We also find evidence of hysteresis: the climate must cool back down beyond the tipping thresholds in order for each cavity to return to its original cold state. Even if the oceanography recovers, the ice sheet does not: sea level contribution from each catchment takes centuries even to stabilise, and the ice does not begin to regrow on this timescale. Therefore, if the Ross or Filchner-Ronne Ice Shelves cross tipping points, the resulting sea level rise will be effectively irreversible.

Speaker: Kaitlin Naughten, British Antarctic Survey
Wednesday 19 March 2025, 14:00-15:00
Venue: BAS Seminar Room 2.
Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Wed 19 Mar 14:00: Tipping points of the Ross and Filchner-Ronne Ice Shelves: how worried should we be?

Conservation Talks - Wed, 26/02/2025 - 09:05

Tipping points of the Ross and Filchner-Ronne Ice Shelves: how worried should we be?

Ocean models consistently project that with sufficient climate change forcing, the Ross and Filchner-Ronne ice shelf cavities could abruptly transition from a cold state to a warm state. Crossing these tipping points would have profound consequences for basal melt rates, buttressing of ice streams, and ultimately sea level rise. Here we analyse over 14,000 years of “overshoot” simulations with the UK Earth System Model, which includes a fully coupled Antarctic Ice Sheet. As the climate warms, stabilises at different temperatures, and cools again, we simulate many examples of the cavities tipping and recovering. We find that global warming thresholds of around 3.5°C and 5°C tip the Ross and Filchner-Ronne respectively. We also find evidence of hysteresis: the climate must cool back down beyond the tipping thresholds in order for each cavity to return to its original cold state. Even if the oceanography recovers, the ice sheet does not: sea level contribution from each catchment takes centuries even to stabilise, and the ice does not begin to regrow on this timescale. Therefore, if the Ross or Filchner-Ronne Ice Shelves cross tipping points, the resulting sea level rise will be effectively irreversible.

Speaker: Kaitlin Naughten, British Antarctic Survey
Wednesday 19 March 2025, 14:00-15:00
Venue: BAS Seminar Room 2.
Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

Add to your calendar or Include in your list

Wed 19 Mar 14:00: Tipping points of the Ross and Filchner-Ronne Ice Shelves: how worried should we be?

Conservation at Cambridge - Wed, 26/02/2025 - 09:05

Tipping points of the Ross and Filchner-Ronne Ice Shelves: how worried should we be?

Ocean models consistently project that with sufficient climate change forcing, the Ross and Filchner-Ronne ice shelf cavities could abruptly transition from a cold state to a warm state. Crossing these tipping points would have profound consequences for basal melt rates, buttressing of ice streams, and ultimately sea level rise. Here we analyse over 14,000 years of “overshoot” simulations with the UK Earth System Model, which includes a fully coupled Antarctic Ice Sheet. As the climate warms, stabilises at different temperatures, and cools again, we simulate many examples of the cavities tipping and recovering. We find that global warming thresholds of around 3.5°C and 5°C tip the Ross and Filchner-Ronne respectively. We also find evidence of hysteresis: the climate must cool back down beyond the tipping thresholds in order for each cavity to return to its original cold state. Even if the oceanography recovers, the ice sheet does not: sea level contribution from each catchment takes centuries even to stabilise, and the ice does not begin to regrow on this timescale. Therefore, if the Ross or Filchner-Ronne Ice Shelves cross tipping points, the resulting sea level rise will be effectively irreversible.

Speaker: Kaitlin Naughten, British Antarctic Survey
Wednesday 19 March 2025, 14:00-15:00
Venue: BAS Seminar Room 2.
Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

Add to your calendar or Include in your list

Wed 26 Feb 15:30: The Impacts of Freshwater Transport on the Weddell Gyre Carbon Budget

Conservation-related talks - Wed, 26/02/2025 - 09:00

The Impacts of Freshwater Transport on the Weddell Gyre Carbon Budget

The Weddell Gyre mediates carbon exchange between the abyssal ocean and atmosphere, which is critical to global climate. This region also features large and highly variable freshwater fluxes due to seasonal sea ice, net precipitation, and glacial melt; however, the impact of these freshwater fluxes on the regional carbon cycle has not been fully explored. Using a novel budget analysis of dissolved inorganic carbon (DIC) mass in the Biogeochemical Southern Ocean State Estimate and revisiting hydrographic analysis from the ANDREX cruises, we highlight two freshwater-driven transports. Where freshwater with minimal DIC enters the ocean, it displaces DIC -rich seawater outwards, driving a lateral transport of 75±5 Tg DIC /year. Additionally, sea ice export requires a compensating import of seawater, which carries 48±11 Tg DIC /year into the gyre. Though often overlooked, these freshwater displacement effects are of leading order in the Weddell Gyre carbon budget in the state estimate and in regrouped box-inversion estimates. Implications for evaluating basin-scale carbon transports are considered. [Time permitting, I’ll also share some results on the role of heat addition in driving circulation change and warming patterns in the Indian sector of the Southern Ocean.]

Speaker: Benjamin Taylor, Scripps Institution of Oceanography
Wednesday 26 February 2025, 15:30-16:30
Venue: BAS Seminar Room 1; https://bas-ac-uk.zoom.us/j/92446999952.
Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

Add to your calendar or Include in your list

Wed 26 Feb 15:30: The Impacts of Freshwater Transport on the Weddell Gyre Carbon Budget

Conservation Talks - Wed, 26/02/2025 - 09:00

The Impacts of Freshwater Transport on the Weddell Gyre Carbon Budget

The Weddell Gyre mediates carbon exchange between the abyssal ocean and atmosphere, which is critical to global climate. This region also features large and highly variable freshwater fluxes due to seasonal sea ice, net precipitation, and glacial melt; however, the impact of these freshwater fluxes on the regional carbon cycle has not been fully explored. Using a novel budget analysis of dissolved inorganic carbon (DIC) mass in the Biogeochemical Southern Ocean State Estimate and revisiting hydrographic analysis from the ANDREX cruises, we highlight two freshwater-driven transports. Where freshwater with minimal DIC enters the ocean, it displaces DIC -rich seawater outwards, driving a lateral transport of 75±5 Tg DIC /year. Additionally, sea ice export requires a compensating import of seawater, which carries 48±11 Tg DIC /year into the gyre. Though often overlooked, these freshwater displacement effects are of leading order in the Weddell Gyre carbon budget in the state estimate and in regrouped box-inversion estimates. Implications for evaluating basin-scale carbon transports are considered. [Time permitting, I’ll also share some results on the role of heat addition in driving circulation change and warming patterns in the Indian sector of the Southern Ocean.]

Speaker: Benjamin Taylor, Scripps Institution of Oceanography
Wednesday 26 February 2025, 15:30-16:30
Venue: BAS Seminar Room 1; https://bas-ac-uk.zoom.us/j/92446999952.
Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

Add to your calendar or Include in your list

Wed 26 Feb 15:30: The Impacts of Freshwater Transport on the Weddell Gyre Carbon Budget

Conservation at Cambridge - Wed, 26/02/2025 - 09:00

The Impacts of Freshwater Transport on the Weddell Gyre Carbon Budget

The Weddell Gyre mediates carbon exchange between the abyssal ocean and atmosphere, which is critical to global climate. This region also features large and highly variable freshwater fluxes due to seasonal sea ice, net precipitation, and glacial melt; however, the impact of these freshwater fluxes on the regional carbon cycle has not been fully explored. Using a novel budget analysis of dissolved inorganic carbon (DIC) mass in the Biogeochemical Southern Ocean State Estimate and revisiting hydrographic analysis from the ANDREX cruises, we highlight two freshwater-driven transports. Where freshwater with minimal DIC enters the ocean, it displaces DIC -rich seawater outwards, driving a lateral transport of 75±5 Tg DIC /year. Additionally, sea ice export requires a compensating import of seawater, which carries 48±11 Tg DIC /year into the gyre. Though often overlooked, these freshwater displacement effects are of leading order in the Weddell Gyre carbon budget in the state estimate and in regrouped box-inversion estimates. Implications for evaluating basin-scale carbon transports are considered. [Time permitting, I’ll also share some results on the role of heat addition in driving circulation change and warming patterns in the Indian sector of the Southern Ocean.]