The song of the Lesser Goldfinch: Another harbinger of a warming climate

As the climate warms, different thresholds are crossed for different species at different times. For the Lesser Goldfinch, that time seems to be now—both in the core and northern edges of its range, where the species is increasing, and in some parts of the southern arid regions, where it is decreasing.

As I prepare to migrate myself from Davis, California to Port Townsend, Washington, I’m serenaded by Lesser Goldfinches every time I step outside. This is a new thing, a warning of coming heat and smoke brought by a beautiful voice. A more open and arid country version of the American Goldfinch, until five or ten years ago, Lesser Goldfinches were sparse breeders in Davis. I would get a few of them mixed with Americans at my feeder in winter, but I’d have to go west to the more arid edges of the Sacramento Valley, or up into the hot dry foothills, to find them in the breeding season.

They arrived in my neighborhood as nesters about five years ago. This year, 2021, they seem to be the most ubiquitous singing bird, setting up terrorities throughout the town. Friends in Sacramento have reported the same. This comes after several years of record heat and lack of rain (only 6″ in all of 2020).

Here’s what the eBird data says. For comparison, Northern Mockingbird, one of the most common birds in town, is reported from about 20 eBird locations in Davis each June (ranging from 16 in 2015 and 14 in 2016 to 18-22 in the more recent years as eBird users and reports increased). Using mockingbird as a metric for Davis, it’d be fair to say that 20 sites represents close to 100% presence throughout the town, and that number was probably 25% lower (i.e. 15 sites) in 2015. Lesser Goldfinches have increased from reports from four sites in June of 2015 (representing about 20% of the town) to 17 sites in June of 2020 (representing 85% of the town). It feels like it will be 100% this year.

They are not the only arid-country species increasing in Davis as a breeder. Nesting Say’s Phoebes have expanded up from the south, with multiple pairs in Woodland each year (and it’s looking like Davis this year as well).

As with so many less-migratory species, Lesser Goldfinches are expanding north into the Pacific Northwest and beyond.  Their colonization of the Columbia River Valley began in the 1950s, with the first state of Washington record in 1951; they are now established around Portland, The Dalles, and in the vicinity of Clarkston on the Idaho border. They remain rare elsewhere, but increases in records have been dramatic in recent years. In the northern Puget Trough region (Chehalis north thru Puget Sound to Canada), June records have increased from 1 in 2015 and 2016 to 10 in 2020 (as reported on eBird). While they have clearly gained a toe-hold in Olympia and Puyallup in the South Sound region, in 2020 they made appearances in Victoria and Vancouver, Canada (not shown in the data because these records were in May, not June).

Lesser Goldfinches in British Columbia were limited to four scattered records until 2007. Since then, they have become nearly annual, with most records between January and June.

This is a pattern seen in other resident and less-migratory species. Many of those that were already growing before detectable climate change (around 1985) have expanded noticeably since then. Anna’s Hummingbird is the most dramatic example.

Further east, Lesser Goldfinches are moving due north from Yakima and Kennewick into the Okanagan Valley. June records in this region have increased from zero in 2015 to eight in 2020.

All this is predicted. The National Audubon climate prediction map for Lesser Goldfinch, under the 2C warming scenario, describes much of what we are witnessing.

In the Mojave Desert, Lesser Goldfinches have declined. Iknayan and Beissinger (2018) reported them from only 43% of 61 study sites, compared to 68% historically. This is part of a massive avian community collapse in the Mojave Desert, as extreme aridity is pushing many species beyond their limits.

Faster all the time: The basics of sea level rise

I was lucky to be out of town for a week during “the greatest statewide heat wave ever recorded in California.” When I arrived in Seattle, I was quickly informed that they had just set a record of 55 consecutive days without rain—and that the record would still be increasing had it not been for 0.02 inches late one night a few weeks earlier. Seattle has also set a number of heat records the past four summers. The same people that bragged about this “beautiful weather” scoffed that I believed in climate change. They asserted that no sea level rise would occur during our, our children’s, or our grandchildren’s lifetimes because, 1) Puget Sound was not really part of the ocean; and 2) those NOAA flood maps are “bureaucratic bullshit”.  These same people live on the water in homes that are a few feet above current maximum high tides. Days later we all swept ashes off decks while marveling at the sun, which was reduced to a rosy red disc by smoke from a record 68 large uncontained fires burning across the West.

Astounded by the number of homes, roads, and railroad tracks located just toe-dipping distance above Puget Sound, I set out to learn about sea level rise, talking to experts and reading published studies and reports from the Intergovernmental Panel on Climate Change (IPCC) .  Here are the basics.

  • Increases in sea level lag quite a bit behind climate change. We set the record for the warmest year on earth in 2016, breaking the record from 2015, which broke the record from 2014. For something as variable as weather, which has all kinds of ups and downs, this kind of consecutive record-breaking suggests runaway global warming. It is dramatic. But not so with sea levels.
  • Sea level rise is a function of several different factors:
    1. Thermal expansion: This happens because, like air or most anything else, water expands when it is warmer, taking up more space. As ocean temperatures increase, they bulge up a bit, and the sea level rises. This can be quantified with pretty good precision and is already occurring. In fact, this explains nearly all of the sea level rise currently underway.
    2. Antarctic Ice Sheet: While melting ice in the Arctic Ocean affects weather and ocean currents, it doesn’t add to the sea level because the ice was already in the ocean to begin with. An ice cube that melts in a glass of water does not change the water level. But glaciers that are on land, like in Antarctica, will flow into the sea when they melt, thus adding to sea levels. They are like an ice cube perched on the edge of the glass, melting into it.
    3. Greenland Ice Cap: While not as big as the Antarctic Ice Sheet, the Greenland Ice Cap will melt faster. In fact, it is already becoming the next big contributor to sea level rise.
    4. Other glaciers and other factors: Smaller glaciers from Alaska to New Zealand are melting, and also adding to sea level.
  • Sea level rise is underway, currently at a rate of 3.2 mm/yr (about a foot per 100 years). It has already risen 2 ½ inches since the year 2000, and 6 ½ inches since 1900.

  • The rate of sea level rise is increasing as ice melt from Greenland, Antarctica, and other glaciers begin to contribute. The standard practice is to estimate total sea level rise by the year 2100 as compared to 2000. Because the rate is increasing, it will certainly be more than the one foot described above, because ice melt from Greenland, Antarctica, and other places is just beginning. However, estimating that increase is difficult. The 2013 report from the IPCC estimated total sea level rise by 2100 at 1 foot to 3.2 feet, depending upon assumptions about CO2 levels. Because Greenland and other Arctic glaciers are melting faster than anticipated, the IPCC report has come under criticism from scientists, who have now adjusted their estimates up to 1.7 feet to possibly 6 feet by 2100. (Revision from November 2017:  A new study estimates sea level rise at 6 to 11 feet by 2100.)

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The projected range of sea level rise, depicted in scale over a waterfront home.

  • The rate of sea level rise will continue to increase at an increasing rate for several hundred years. The Antarctic Ice Sheet and Greenland have a lot of ice, and melting takes time. This melting, which is only just beginning, will increase with time, but may still take hundreds of years to really pick up steam. This appears to be “virtually certain”. The Antarctic Ice Sheet is now considered to be “past the point of no return”, with large scale melting “unstoppable.” Still, the exact timing is unknown. It will begin slowly but then suddenly increase rapidly, possibly during this century. This caveat is included in all predictions. The “conservative” estimate is that ocean levels will rise 3 to 10 feet by the year 2300, depending upon future CO2 levels and temperature increases. At that point, however, it will still be rising at a rate more than double the current rate. It thus appears that a total sea level rise over 10 feet, largely if not entirely due to anthropogenic CO2 emissions, is inevitable in the long run.
  • In the next few decades, sea level rise will be mostly felt during acute events, such as during high tides or large storms, or a combination of the two. This will, unfortunately, cause my friends in Puget Sound to attribute their flooded living rooms to unusually high tides or large storms, but not to rising sea levels.

To examine flooding in Puget Sound under various levels of sea level rise, you can surf a map and toggle the level of sea level rise at this interactive website.