Butterflies in Finland ... to starfish in Monterey Bay
Photo by FortPhoto
Guest post from Camille Parmesan, Associate Professor of Integrative Biology at the University of Texas.
Responses to climate change are so ubiquitous and consistent – and systematically showing up in every studied system in every ocean and on every continent – that it’s very clear we have a strong consensus among biologists. That consensus is that recent climate change has impacted wild species and physical systems (glaciers, sea ice, etc.)
The logic of a global focus on biological change is analogous to that for climate change itself.
In the global focus on climate change, attribution of recent warming trends to changes in atmospheric gases comes from analyses of global patterns, not from detailed data from individual meteorological stations. Likewise, when assessing biological impacts, global pattern of change is far more important than any individual study.
The biologists’ approach selects study systems to minimize confounding factors and deduces a strong climate signal both from systematic trends across studies and from empirically derived links between climate and biological systems.
Seventy–four to 91% of species that have changed have done so in accord with climate change predictions.
We are seeing impacts of current warming on every continent and in every ocean. We’re also seeing very similar responses in very different types of organisms – from butterflies in Finland to fish in the North Sea, from foxes in Canada to trees in Sweden, from birds in Antarctica to starfish in Monterey Bay, California.
Forty–percent of wild species are showing changes in their distributions – shifting their ranges north and south towards the poles and up mountains. An astonishing 62% are showing changes in their seasonal timing: spring is earlier and fall is later. Birds arriving for their spring migration, butterflies emerging from overwintering, trees leafing out after winter dormancy and the first blooms of flowers are all about two weeks earlier than they were 30 years ago across the northern hemisphere.
My colleague, economist Gary Yohe, recognized that this was what economists would call a “globally coherent” signal of climate change impacts in natural systems across the world.
This coherence – this systematic pattern – is important because it tells us that species and systems for which we don’t have any data are likely to be showing similar responses to those with detailed, long–term data. Globally, we estimated that half of all wild plants and animals have been affected by recent, human–driven climate change.
What are the possible future worlds?
All of the changes I talk about above have occurred with just 0.7° C warming. Even the minimum projections – of another 1.8° C – are more than twice what we’ve already seen. “Business as usual” projections are for another 4° C rise, with some models estimating over 6° C rise in global temperature.
It doesn’t take a scientist to tell what might happen if warming is allowed to reach the upper projections. The fact is that we’ve already had 74 species of cloud forest frogs go extinct, massive die offs of coral reefs, and severe declines in polar and mountaintop species. All that, with only 0.7 Deg. C warming.
It’s only common sense that species’ extinctions will increase even with the minimum projected warming, and that major changes in life on Earth will occur if we go to the highest projections.
