Predictions of future climate change are often dire, but they can be difficult for us to really comprehend. Annual average temperatures several degrees above what we’re used to, rising sea levels, and more severe storms and drought cycles are all in our future, and it's sometimes hard to imagine how these things will impact our lives.
This week, European and American political leaders issued new reports aimed at helping us all imagine these scenarios a little more clearly. Both highlight the economic impacts of flooding, farm yields, human health and mortality, and other effects. The European Union’s Joint Research Centre says climate change could cause €190 billion in losses and 200,000 heat-related deaths, for instance.
The American report, called "Risky Business," opens on a photo of post-Hurricane Sandy Seaside Heights, N.J., with a roller coaster in the water. It says higher sea levels combined with storm surges will likely bring the average annual cost of coastal storms to $3.5 billion, a $2 billion increase. It also says to expect crop losses of 10 to 20 percent, among many other dire predictions.
All these negative effects are in our future if we do nothing, the reports say. But climate change is also very much in our present. Humans are already having an impact on the Earth, and you can see it happening now, no imagination required. Here are four big ways in which climate change is already affecting our planet.
Glaciers are Melting, Often Irreversibly
A late spring this year brought an avalanche of bad glacier news. The West Antarctic Ice Sheet has started to collapse, starting a centuries-long process that will culminate in sea levels 15 feet higher than they are now. There is nothing we can do about it.
“Previously, when we saw thinning we didn't necessarily know whether the glacier could slow down later, spontaneously or through some feedback,” says Ian Joughin, a glaciologist at the University of Washington’s Applied Physics Laboratory. "In our model simulations, it looks like all the feedback tends to point toward it actually accelerating over time; there’s no real stabilizing mechanism we can see."
Warmer polar water is melting the glacier’s underside, which is weakening the entire floating shelf. It’s no surprise, given earlier findings that the entire Antarctic has been warming up for 60 years. The average temperature of the coldest days on the Antarctic Peninsula has soared by 14°C, which correlates with atmospheric carbon dioxide levels, according to a 2011 study.
Plants and Trees are Flowering Earlier
Around the world, growing seasons are changing, especially in the middle and high latitudes on Earth. This is partly due to an earlier spring and partly because of a later fall, according to the Intergovernmental Panel on Climate Change.
“Leaf unfolding and flowering in spring and summer have, on average, advanced by 1-3 days per decade in Europe, North America and Japan over the last 30 to 50 years,” the IPCC says.
The public already knows it, if subconsciously. In a 2012 paper, researchers at the University of North Carolina-Chapel Hill found peak attendance in U.S. national parks that are experiencing climate change has shifted 4 to 6 days earlier since 1979. While all parks see a jump in attendance when it’s warm, the shift in the last 35 years tracks with increasing temperatures in the parks.
One of the most interesting examples comes straight from the diaries of Henry David Thoreau. He kept detailed journals about his walks in Concord, Mass., including when flowers first bloomed and when insects first showed up in spring. Scientists who are comparing notes with Thoreau find that not only are some flowers blooming earlier in the spring, they’re out-competing other species: flowers that can’t adjust as easily aren’t growing there anymore.
Animal and Plant Ranges are Changing
The loss of some native Concord flowers is just one example of the ways in which plant and animal ranges are changing. In 2011, researchers writing in Science found the distributions of species have shifted to higher elevations and latitudes two and three times faster than previously reported. Elevations rose by a median rate of 36 feet per decade, and latitudes shifted at a median rate of 10 miles per decade, the authors say. The more warming a region is experiencing, the greater the shifts are happening, the report says. It looked at species in Europe, North America, Chile, and Malaysia.
The cute, furry pika is a great example of this phenomenon. In a different 2011 study, scientists found this mountain-living rodent used to move upslope at about 43 feet per decade. Since the late 1990s, they have moved up a whopping 475 feet per decade.
Though habitat change and loss is bad news for the animals and plants themselves, it could be very bad news for us, too. One key reason is disease. Animals and insects are vectors for several nasty ailments, from malaria and dengue fever to plague and sleeping sickness. Insects could change altitudes and latitudes, too, bringing diseases like malaria to regions that have never experienced it.
Global Temperatures are Already Higher and the Atmosphere Contains More CO2
The Earth's average temperature has increased about 1 degree Fahrenheit during the 20th century, according to NASA. While this may not sound like a lot, it’s a major jump compared to natural fluctuations, which scientists measure in tree rings, ice cores, and coral reefs. And atmospheric CO2 is on the rise, also much faster than would be expected for natural changes.
The "Risky Business" report, like most climate research, projects changes that are expected by 2100. How bad it gets depends on how much more greenhouse gas we release, so predictions vary. While that date may seem far away to policymakers, "climate impacts are unusual in that future risks are directly tied to present decisions," the report says. To that end, it may help to consider present risks and changes, too.