The world has been in a similar climate pattern for about 10,000 years, or since the end of the last Ice Age and the transition to ‘modern’ times, called the Holocene by geologists. This is the time of the slow but steady rise of civilization as we know it, including farming culture (agri-culture), the domestication of many animals and plants, urban centers, etc., and the five recognized prehistoric centers of higher culture – Meso-America; greater Peru; the Middle East; China; and India.
Rapid Change Is Here
Children born today will never know that world. We are already transitioning out of that ‘old normal,’ and yet because things are still changing, and rapidly, we have not yet arrived at the new normal. Things are changing much more rapidly than just 10-15 years ago, when the prevailing wisdom was that climate change effects would manifest, if at all, sometime in a vague and distant future. Yet 2023 was the hottest year on record worldwide. It was itself reportedly consistent with a 1.5 degree rise in temperatures. 2024 is also expected to be very hot, possibly hotter than 2023. This doesn’t mean we’ve already reached the 1.5 degree threshold – things could get cooler again in the future. But we are clearly well on our way to a difficult climate future.
But things are already entering a period with a growing degree of chaos and uncertainty. Places once hospitable to human life are becoming less and less so, even crossing thresholds to where people see more and more clearly the writing on the wall, and are beginning to be on the move. Heat, drought, floods, wildfires, sea level changes, are multiplying misery, straining livelihoods, and exacerbating already fragile levels of peace. Regimes feel more threatened and increase authoritarian and military approaches to their own people and others. Migration soars, and so it appears to be doing in both Europe and the US and Canada.
But in addition to the direct human toll of climate change, agricultural operations will have to shift in response to increased heat and changes in growing zones across the planet. The USDA’s most recent plant hardiness map (2023) reveals that about half of the country shifted to the next warmer half zone (since 2012), while the other half of the country remained in the same half zone. And Nature and all the other living beings in the world are also deeply effected by these planetary changes They too are collectively harmed, both as individuals and as communities, sometimes devastated, by extreme weather events, floods, fires, heat, hurricanes. And they are stirring and moving in response to longer term warming, hot nights, and shifting seasons, adapting the best they can with limited tools to imperfect circumstances.
Effect on Plants and Animals
It has long been known that animals and even plants need to move, and are impelled to move, whether it be for juveniles to spread into new territories, in response to seasonal changes, in response to natural disasters, in response to overcrowding, to avoid isolation, and so on. The belated creation of wildlife corridors for those purposes has been a bit of a cause célèbres of late, and there are many plans to create corridors in many states, some dating back decades, sometimes ironically led by states’ transportation departments since roads and the traffic and the ‘development’ that follows are our primary fragmenting feature. Still, wildlife corridor creation has never ‘gone mainstream,’ and has not been implemented nearly often enough to avoid most habitat fragmentation problems. There never seems to be enough time or money to prioritize these ‘afterthoughts’ in a culture that is constantly engaged in a mad scramble for resources and money-making.
But climate change is challenging everything as never before. Animals and plants generally will need to move north and upslope in response to climate change. Ocean organisms may be able to move north or go into deeper waters, although in the case of the ocean, currents themselves may change, at times and in ways we do not yet understand. As the ocean has warmed, west coast albacore tuna migrations have already moved further offshore, sometimes up to 1,000 miles further, making fishing for them more expensive and time-consuming.
Climate change is happening very quickly. Many organisms may not be able to adapt, to shift their ranges to new, suitable habitat, quickly enough. Or they may not have the opportunity. Most reptiles and small mammals may be expected to have difficulty shifting in time. For example, it is difficult to imagine the desert tortoise hustling north, shifting their range fast enough to keep up with rapid onset climate change. They will likely have to hunker down more or less in place. Plants whose seeds are not wind-borne may also have difficulty, depending on their specific strategies. And there are special cases – for example, there is a single patch of an endemic lupine sub-species that lives only on the isolated top of Mt. Ashland, Oregon. It has nowhere to migrate to, except perhaps to ‘beam up.’
How Birds Are Effected by Climate Change
Birds might be expected to have the easiest time of it, as of course they can simply fly somewhere else. But a recent study – called Survival By Degrees: 389 Bird Species on the Brink – by the National Audubon Society combined a staggering 140 million bits of data collected by the army of volunteer citizen scientist birders to plot where 604 bird’s ranges are likely to shift to under various future climate warming scenarios. They used the same climate models that have been used by more than 800 climate experts, and modeled summer habitat separately from winter habitat. Changes in temperatures, precipitation, and vegetation were each assessed, and more. Additional climate change-related threats considered in this analysis included sea level rise and lake level change; urbanization; cropland expansion; and extreme weather events, including extreme spring heat, fire weather, spring droughts, heavy rains, and false springs.
The findings are shocking – that 389 of the 604 species (64%, or about two-thirds) are at highly or moderately vulnerable under a 3 degree C average temperature rise scenario. This number could be reduced by ¾ if temperature rises were kept to the international goal of 1.5 degrees.
The study divided all North American birds into 12 habitat groups, and found that four of them were highly vulnerable to the worse end of climate change; four were moderately vulnerable; and four were mildly vulnerable. The most vulnerable were arctic species (100% of 16 species); boreal species (98% of 48 species); western forest species (86% of 73 species);and waterbirds (78% of 85 species).
Increases of as little as a half a degree centigrade can make a big difference for many species, the study found. The difference between a 1.5 versus a 2 degree rise resulted in 41 more species being at risk. Breeding habitat was more at risk than winter non-breeding habitat. “Extreme spring heat can directly affect birds through heat stress, which can lead to mass mortality events, and subsequently reduce populations and species richness locally.”
Extreme heat during breeding season is a widespread threat, one that covers large areas and many species. Spring can include what are called ‘false springs’ too, when plants begin to grow early due to ‘false’ warm temperature signals, and then a hard freeze occurs, killing or damaging the new buds, leaves, or even insect hatches. This can throw off the previously synchronized timing of insect hatchings, typically a birds’ main source of food, with the birth of the chicks. Extreme heat puts newborn chicks particularly at risk due to their extra sensitivity. It is especially hard if it is combined with another climate related difficulty like drought, flooding, or fire.
Sea level rise, by contrast, has a smaller and more focused, but even more disproportionate, impact. It covers less than 1% in area based on median sea level rise estimates for even a 3.0°C warming scenario, yet it was projected by the study to affect 5% and 9% of breeding and non-breeding species. It is projected to be the worst in Florida, Louisiana, Texas, and North Carolina.
Of course all this is happening at a time when many birds are already threatened with population reductions and even extinction due to habitat loss, pollution, and other manmade causes.
The Audubon report also includes links to state-by-state summaries of expected affects. Many states that host birds at the southern end of their ranges could lose those species as they move northwards. Even now common ‘backyard’ birds could disappear as change deepens in future years. “Highly vulnerable birds include iconic North Carolina birds such as the Wood Thrush, Brown-headed Nuthatch, Red-headed Woodpecker, and Golden-winged Warbler and many others. These are birds that all of us know well from our backyards.” Hundreds of species could lose more than half of their current ranges.
Luckily, the report does not simply paint a dire picture of the future and leave us there helpless. There are many positive actions and policy changes discussed as well, many of which are well-known, such as habitat restoration, use of natural infrastructure where needed, such as along coasts and rivers, reforestation, implementation of wildlife corridors, and so on.
Perhaps most importantly though, this report lights a fire under us, reminding us of what an unprecedented emergency climate change actually is, and rousing us from any complacency and apathy in a new way. Birds are probably the only group of species that provides such a wealth of data, involving so many hours of heartfelt dedication from so many ‘bird lovers,’ could lead to such a report. Survival By Degrees: 389 Bird Species on the Brink is well worth reading, and is readily available via the National Audubon Society’s website.
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