What you need to know
In the best case scenario we will lose corals and the Arctic even if we transition at an abrupt and societally transformative pace.
What does a world that is just 1.5 degrees Celsius warmer look like? Think clear, ice-free seas in the Arctic. Irreversible loss of coral reefs and edible fish stocks. A news cycle dominated by devastating climatic events. Plant and animal extinctions at unprecedented rates.
Yes, the new Intergovernmental Panel on Climate Change report on how to keep the world below 1.5 degrees Celsius of average warming, and therefore significant levels of destruction, makes for grim reading.
But while the underlying science and models used to estimate future impacts is complex, it’s important to understand what a warming world will look like in order to best mitigate the fallout.
Luckily, the report uses clear figures to convey future damages.
Our changing planet
This graph concisely summarizes hundreds of pages of the report, so let’s get unpacking! The gray bar is the baseline scenario that we currently live in. To the left, you can see different temperature scenarios, where color indicates the scale of impact.
Purple is very high or significant risk. In other words, purple means that those systems will disappear as we know them, completely transforming. In dramatic terms, they will die.
Warm water corals, small-scale and low-latitude (tropical) fisheries, the Arctic, and coastal regions face dire threats. These systems as we know them will essentially disappear or re-shape even in aggressive carbon reduction scenarios.
The first commercial vessel recently passed over the Arctic during winter without an icebreaker. During the last El Nino corals all over the world fell to bleaching, and we have seen a frightening amount of hurricanes and floods in the past two years.
Imagine the news of climate disasters you are used to reading multiplied by 100, and you have the 1.5 C or 2 C warmer world.
Corals and low-latitude fisheries provide a significant source of protein for almost 1 billion people. If corals cease to function, it would create a global food crisis. Unlike agriculture, we cannot grow more corals. Once they are truly gone, their habitats will be so drastically changed that they can never return.
Next, terrestrial ecosystems will change massively. With rising temperatures, plants, the foundations of ecosystems, will also shift. Unlike animals, plants can’t really move, so if the climate changes to an inhospitable one, they will die, these deaths will shape ecosystems in profound ways.
In the words of the report: “Of 105,000 species studied, 6 percent of insects, 8 percent of plants and 4 percent of vertebrates are projected to lose over half of their climatically determined geographic range for global warming of 1.5 C, compared with 18 percent of insects, 16 percent of plants and 8 percent of vertebrates for global warming of 2 C.
Impacts associated with other biodiversity related risks such as forest fires, and the spread of invasive species, are lower at 1.5 C compared to 2 C of global warming (high confidence).”
This means that even a 5 C average increase will more than double the amount of insects plants and vertebrates impacted. This rate will likely increase dramatically as we go beyond 2 C, which at present rates is virtually assured.
An animal losing half of its habitat on top of existing habitat loss threats can be an extinction sentence. Many animals have evolved to fit a specific ecological niche, such as certain valleys or certain forests, without sufficient time to adapt to a rapidly warming world, they will certainly perish.
The two final points worth highlighting from these impact ranges are crop yields and heat-related mortality. With changing rain patterns, flooding, and temperatures it will become increasingly difficult to grow crops in certain parts of the world.
Mangroves, while not purple or red, will decline as well. This poses a serious problem for already storm prone areas as mangroves act as the first layer of coastal defense. With habitat loss already destroying mangrove ecosystems we are literally tearing down our own protective walls. Climate change will just accelerate this process causing a positive feedback loop of storm vulnerability.
Likewise for cities, rising temperatures on top of existing heat from the “urban heat island effect” (cities are hotter because of asphalt and concrete) will make certain cities unlivable.
The whole world is getting hotter, wetter, and drier
Scientists use the term climate change, instead of global warming, because it more accurately describes (in neutral terms), what is happening. While the global average temperature is increasing, this has many other related impacts.
Two key areas to read on these maps are the Arctic and the continental landmasses of the northern hemisphere.
The coldest nights in the Arctic will be 10 C hotter, and that could mean the difference between freezing and melting in a region that depends on that frost to function. Researchers are already seeing this change occur.
Looking at the hottest days on the northern hemisphere continents, we will see a temperature increase of 4 to 6 C on the hottest days in the western U.S. Arizona’s already hot weather could become simply unlivable.
Researchers estimate that the percentage of global population that experiences deadly heat for at least 20 days a year will increase from 30 percent to 74 percent by 2100 under medium to high carbon scenarios.
Looking at precipitation we see a general increase of 10 to 15 percent across the world during extreme rain events. While seemingly small that increase could be the difference for flood infrastructure to hold. In either scenario, infrastructure costs will continue to climb as more frequent and stronger storms occur.
In short, these maps show a world of intensity. Climate change by itself will impact certain systems strongly: corals, forest-based ecosystems and more, at a speed that nature simply cannot evolve with. However, these impacts become amplified when you pile on existing human impacts such as deforestation, land-based pollution, industrial farming, cities, and every other anthropogenic negative.
Thus, in the face of climate hopelessness, we must think of climate change as a great amplifier of problems. True we can reduce our carbon output, but we can also make an impact in our local areas. By supporting forest restoration efforts, by preventing harmful fishing practices near coral, by limiting industrial runoff.
To those in the environmental community, this report won’t come as much of a surprise. With the focus on the COP 21 Paris Treaty many believed that 2 C was enough average warming for the world and we could survive it. Yet at that time I can recall delegates lamenting that even 2 C was too much, that 1.5 C was the only way to avoid positive feedback loops and lasting permanent damage.
This research brought together to show that point makes the strongest possible case for rapid decarbonization. To be blunt, even in the best-case scenario we will lose corals and the Arctic even if we transition at an abrupt and societally transformative pace.
What can we do?
Scientists approach climate change in two ways: first mitigation and then adaptation. For mitigation, it’s the standard list: eat less meat, purchase renewable energy, offset, and use more public transit (ideally biking). Yet when faced with ecosystem change, our best option is in fact conservation. To protect these ecosystems as much as possible from harmful industrial activities and exploitation.
If you live in a democracy, you can attend environmental impact assessment meetings in your area for proposed development. Having attended many, I can tell you that they are scarcely attended and without public comment developers often get free reign. Donating to conservation non-profits like the Sierra Club also help safe-guard natural areas.
For adaptation, well, you have the maps. For many the sad reality will require leaving their homes. Those with privilege and capital can choose. However, for the estimated 150 million others by 2050, they will become “climate refugees.” In a world that already forces additional obstacles on displaced peoples, the climate will make it even harder.
As an amplifier climate change will make refugee crises worse as floods, droughts, famines, and heatwaves rock already vulnerable and volatile parts of the world.
Supporting resilience in communities, building strong refugee support networks now in anticipation of future movements will become vital.
Just as things become direr, so too does hope grow. A hotter world is not without opportunity for restoration and compassion. This information is meant to empower not immobilize, only by understanding the severity of these challenges can people start organizing equitable and effective solutions to meet them before they cause catastrophe.