Carbon dioxide levels highest in human history

Atmospheric levels of planet-warming carbon dioxide have hit a record high of more than 415 parts per million. The accelerated rise of man-made greenhouse gas emissions has scientists alarmed.

The concentration of carbon dioxide in the Earth's atmosphere has reached a record high, according to scientists at the Scripps Institution of Oceanography in the US.

The Mauna Loa Observatory in Hawaii recorded a carbon dioxide level of 415.39 parts per million (ppm) on Saturday, marking the first time a reading of the greenhouse gas has measured over 415 ppm.

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The last time there was more carbon dioxide in the atmosphere was more than 3 million years ago, when global average temperatures were 3 or 4 degrees Celsius (5.4-7.2 degrees Fahrenheit) higher than today, the oceans were several meters higher and parts of Antarctica supported forests.

The data has been recorded as part of the Keeling Curve, which started measurements in Mauna Loa in 1958. Since then, carbon dioxide concentrations in the atmosphere have risen 30%.

Read more: Climate change: Millions of hectares of tropical forest destroyed in 2018

Prior to the Industrial Revolution in the 19th century, carbon dioxide levels fluctuated but never exceeded 300 ppm at any one time over the past 800,000 years. Carbon dioxide levels in the atmosphere broke 400 ppm for the first time in human history in 2013.

Despite global commitments to reduce greenhouse gases under the 2015 Paris climate accord, the rate of heat trapping gases entering the atmosphere is accelerating. The last four years are the four hottest on record.

Read more: Climate change: Energy-linked CO2 emissions hit record high in 2018

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Ralph Keeling, director of Scripps Institution of Oceanography's CO2 Program, said the trend would probably continue throughout 2019 with the possibility of an El Nino year in which temperatures rise due to warmer ocean currents.

"The average growth rate is remaining on the high end. The increase from last year will probably be around three parts per million whereas the recent average has been 2.5 ppm," he said. "Likely we're seeing the effect of mild El Nino conditions on top of ongoing fossil fuel use."

"Every year it goes up like this we should be saying 'No, this shouldn't be happening. It's not normal.' This increase is just not sustainable in terms of energy use and in terms of what we are doing to the planet," he said.

Under current emission trajectories, carbon dioxide in the atmosphere could reach 1,000 ppm over the next century, according to the Scripps Institution.

Doomsday tourism and climate change: Visiting natural wonders before they disappear

Transient treasure

Of the 2 million-odd people who visit the Great Barrier Reef annually, a 2016 survey found that 69 percent were coming to see the UNESCO World Heritage site "before it's too late." And no wonder. The IPCC says that even if we manage to limit global warming to 2 degrees Celsius, 99 percent of the world's coral will be wiped out. Tourists can hasten their demise by touching or polluting reefs.

Doomsday tourism and climate change: Visiting natural wonders before they disappear

Bearly there

And what's the carbon cost of flying to remote natural wonders under threat? A 2010 study found that the business of polar-bear safaris in Churchill, Canada, had an annual CO2 footprint of 20 megatons. Most visitors arrived by plane, and while 88 percent of them said humans were responsible for climate change, only 69 percent agreed that air travel was a contributing cause.

Doomsday tourism and climate change: Visiting natural wonders before they disappear

Art of the apocalypse

Along with the polar bear, one of the most iconic images of climate change must be the dramatic curves of an iceberg sculpted by the warming atmosphere. Gliding between the melting giants on a cruise ship is a haunting experience that tourists will pay huge sums for. In the early 1990s just 5,000 people visited Antarctica each year, compared to over 46,000 in 2018.

Doomsday tourism and climate change: Visiting natural wonders before they disappear

Peak season

You don't have to go to the poles to see vanishing ice. Kilimanjaro's snowy peaks are a striking sight above the equatorial savannah of the national park, which generates €44 million ($50 million) from tourism annually. Many visitors climb to the Furtwängler Glacier — where 85 percent of the ice has vanished over the last century. The rest is unlikely to survive much beyond mid-century.

Doomsday tourism and climate change: Visiting natural wonders before they disappear

King without a crown

When Montana's Glacier National Park opened in 1910, it boasted over 100 of the ice features from which it took its name. Now, there are fewer than two dozen. So dramatic is their retreat, that the park has become a center of climate science research. Some 3 million hikers and holidaymakers also visit the "crown of the continent" each year, soaking in the dying days of its ice-capped glory.

Doomsday tourism and climate change: Visiting natural wonders before they disappear

Paradise lost

The Maldives are the archetypal tourist paradise: 1,200 coral islands with white beaches rising just 2.5 meters above the turquoise waters. In 2017, the president decided to build new airports and megaresorts to accommodate seven times as many tourists, and use the revenue to build new islands and relocate communities. He has since been voted out of office and faces corruption charges.

Doomsday tourism and climate change: Visiting natural wonders before they disappear

Saltwater swamps

It's not just islands that are going under as sea levels rise. Wetlands like Florida's Everglades are disappearing too. Over the last century, around half the Everglades have been drained and turned over to agriculture. Now, saltwater is seeping into what's left, making it the only critically endangered World Heritage site in the United States.

Doomsday tourism and climate change: Visiting natural wonders before they disappear

Disturbing the peace

The Galapagos will be forever associated with Darwin, who realized their unique wildlife had evolved over countless generations in isolation. Today, they are besieged by visitors and environmental changes are happening too fast for species to adapt. Ocean warming has left iconic creatures like the marine iguana starving, while UNESCO lists tourism among the greatest threats to the archipelago.

cw/cmk (AFP, dpa)

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