Farallon Institute Newsletter - Fall 2021

Around The [Home] Office

FI scientist Julie Thayer was recently invited to join the California Interagency Ecological Program (IEP) Stakeholder Group. The IEP is a consortium of nine member agencies that significantly participates in management of the San Francisco Bay-Delta ecosystem by conducting relevant ecological studies. Julie was invited to join the group due to her influential work on California halibut and herring management using IEP data from San Francisco Bay, and her experience studying the San Francisco Bay fish community in relation to Alcatraz Island seabirds. We’re excited about Julie’s forthcoming contributions to the IEP’s conservation efforts as part of the stakeholder group.

State of the Ocean - According to the recent IPCC Report

Our main takeaways from the report:
- Humans are the cause of the warming climate
- Global temperature has increased by 1.09°C and we will pass 1.5°C (Paris Climate Agreement) by 2040
- Now is the time to act!

On August 11, 2021 we woke up to the news of the release of the 6th Assessment Report of the United Nation’s Intergovernmental Panel for Climate Change (IPCC AR6). It has been eight years since the previous report IPCC AR5. This report represents a massive global effort to update and synthesize all current scientific knowledge on climate change, present and future. The recent release, covering the physical science of climate change, is the first of three parts. The other parts, to be released in future months, are on i) climate change impacts and ii) adaptation and mitigation.

The foremost message of this report is that global warming is unequivocally caused by humans. No news there, but it is the first time the IPCC report has stated it front and center, which signals the need and importance for this message to be heard, accepted, and acted upon. The report also tells us that we have currently warmed the surface of the earth by 1.09°C (~2°F), that the Earth continues warming, and that we are expected to reach 1.5°C warming before 2040, regardless of the level of greenhouse gas emissions in that time. A global warming limit of 1.5°C was the goal of the Paris Climate Agreement.

What’s the current State of the Ocean in relation to Climate Change? As a key component of the climate system, the ocean absorbs about only a quarter of the emitted CO2, but accumulates 91% of the excess energy caused by the anthropogenic global warming. The report states that the upper ocean has warmed up (about 0.88°C or 1.5°F), its oxygen levels have dropped, and it has become more acidic; also, sea level is rising at an accelerated pace. Furthermore, we are also experiencing twice the number of marine heat waves since the 1980s. These changes are unprecedented, not recorded in thousands or millions of years.

While many of the observed changes (in the ocean as well as on land) are irreversible at scales of centuries or millennia, scenarios in which we act decisively to mitigate emissions, and even capture greenhouse gasses for net-zero and negative emissions, show that intense warming can still be avoided. The best time to act was many years ago, but the next best time is today!

Concurrent drought and marine heatwave

From 2013–2016, an exceptional, persistent drought hit California at the same time that an intense marine heatwave formed in the Gulf of Alaska and reached the West Coast, extending all the way south to Baja California, Mexico. This unprecedented combination of extreme events caused significant ecological and socio-economic impacts across the marine and terrestrial realms, including impaired marine productivity, massive die-offs of sea birds, poisoning of marine mammals, reduced terrestrial water supply in California, exacerbated fire seasons, and significant economic losses in fisheries and agriculture.

Will these compound extremes occur more frequently in the future under global warming? Farallon Institute researchers aimed to answer this question by analyzing climate models, and was recently published in Geophysical Research Letters. We found that co-occurring drought and marine heatwave events along the west coast were very unusual in the past. In the future, as the ocean temperature continues to rise and the land continues to dry out due to anthropogenic warming, co-occurrence of similar conditions as today will increase dramatically from about once per century to about four times per decade (Figure, top).

However, if we consider a shifting baseline of what the contemporary “normal” will be in the future, the changes in these compound extremes are much less dramatic or exhibit no change at all (Figure, bottom). For example, models project no changes in the frequency of co-occurring episodes of marine heatwaves in the California Current and California drought in response to warming. The marine heatwaves in Gulf of Alaska will co-occur more frequently with California drought, but the increase is relatively small (from 1.1 to 1.7 per century).

The Intergovernmental Panel on Climate Change recently reported with relatively high certainty that climate change is responsible for the increased frequencies of climate extremes that are occurring around the world; some regions have experienced increased frequencies of two or more types of extreme events. For the U.S. West Coast, our new study lays out the apparent increased risk of compounded extreme conditions, as well as the subtle changes under a shifting baseline, which would likely impact the ecosystem in distinct ways. The authors urge that as the earth continues to rapidly warm, one priority would be to better understand the mechanisms coupling these extreme events to better prepare for future climate change.

Read the full article here.

Alcatraz Island 2021 seabird monitoring update

The seabird breeding season on Alcatraz Island is coming to a close, as most fledglings and adults have left the summer breeding territories in search of ocean upwelling and winter foraging opportunities. This year hosted the largest known seabird colony on Alcatraz, with just over 3,300 breeding pairs of Brandt’s cormorants (over the 2020 record of 2,660 pairs), and almost 950 western gull nests, among several other species on the island.  

The July 4 fireworks display put on by the City of San Francisco and located on barges in the bay between the City and Alcatraz Island typically has negative consequences with the breeding seabirds. The noise and light from the event scare adult cormorants off their nests, leaving the eggs and chicks susceptible to trampling and exposure to the weather. However, with the exceptionally early start to breeding this year, most cormorant chicks were old enough to “crèche” with chicks from nearby nests, so they weathered the evening in safe, warm groups of downy young. Due to this timing of their development, egg and chick loss from the 4th of July celebration was minimal this year, and the breeding season as a whole was a success for the Alcatraz cormorant population.