A collection of climate change headlines from this month…

Earlier this month our planet hit a milestone number: 400 parts per million. That’s the amount of carbon dioxide in our atmosphere. From the Elements blog in the New Yorker:

…the number should shake us, if not shock us. We’ve got more carbon dioxide in the atmosphere now than at any point since the Pliocene, when there were jungles in northern Canada.

What this means for life on Earth is measured, modeled and forecasted by scientists every day. But there’s no doubt that the rise in CO2 is causing global warming. Long gone is the argument that scientists disagree on the matter. A paper published two weeks ago in Environmental Research Letters, determines once again that 97% of researchers agree that current climate change is human-caused.

Melting Ice and Rising Seas

We’ve mentioned the effect of melting Arctic sea ice to sea level rise around the world. A study this month demonstrates that continental glaciers (such as the Greenland one, pictured above) will do even more damage. In fact, another study notes that as glaciers melt in Greenland, the locations of Earth’s poles are changing.

Plants and Animals Feel the Effects

Other recent studies examine the effect of climate change on plants and animals around the globe. Traditional wine-growing locations could be too warm to support vines in the near future. Living in the Arctic, polar bears’ immune systems aren’t as robust as organisms living in warmer climes. With the region warming, researchers are concerned that the iconic white bears could be more vulnerable to disease. Another recent paper reveals that fish and other ocean life are moving toward the poles to escape warming seas. Finally, another paper this month explains (once again) that more than half of common plants and one third of animals could see a dramatic decline this century due to climate change.

Extreme Weather

Can we use Australia as a model of the extreme weather we may see as global warming continues? Time will tell. But even though scientists determined that climate change wasn’t a factor for the recent devastating tornado that hit Oklahoma, scientists believe that future tornados could be more damaging thanks to a warming Earth. Deaths due to heat waves in New York will also increase with climate change, according to a paper last week in Nature Climate Change.

Warming Slowdown?

Another paper last week purports that the world is warming slower than expected and that perhaps we will have a second chance. Will we use the time wisely and reduce our CO2 emissions? What do you think?

Image: Michael Studinger/NASA

A team of scientists, led by Stanford’s Kevin Arrigo, broke through some of the Arctic ice last July as part of the NASA ICESCAPE mission and found the complete opposite—abundant life!

“If someone had asked me before the expedition whether we would see under-ice blooms, I would have told them it was impossible,” says Arrigo. “This discovery was a complete surprise.”

The researchers discovered an abundance of phytoplankton—microscopic life that forms the base of the marine food chain. Phytoplankton require sunlight for photosynthesis, just like plants. And sunlight has a tough time penetrating thick sea ice.

But that thick sea ice is changing. Not only are warmer temperatures thinning the ice, but as the ice melts in summer, it forms pools of water that act like transient skylights and magnifying lenses. These pools focus sunlight through the ice and into the ocean, where currents steer nutrient-rich deep waters up toward the surface. Phytoplankton under the ice evolved to take advantage of this narrow window of light and nutrients.

The phytoplankton displayed extreme activity, doubling in number more than once a day. Blooms in open waters grow at a much slower rate, doubling in two to three days. These growth rates are among the highest ever measured for polar waters. Researchers estimate that phytoplankton production under the ice in parts of the Arctic could be up to 10 times higher than in the nearby open ocean.

The phytoplankton bloom discovered by Arrigo and his colleagues in the Chukchi Sea (just north of Alaska) extends tens of meters deep in spots and about 100 kilometers (62 miles) across.

“At this point we don’t know whether these rich phytoplankton blooms have been happening in the Arctic for a long time and we just haven’t observed them before,” Arrigo says. “These blooms could become more widespread in the future, however, if the Arctic sea ice cover continues to thin.”

The discovery of these previously unknown under-ice blooms could have serious implications for the broader Arctic ecosystem, including migratory species such as whales and birds. Phytoplankton are eaten by small ocean animals, which are eaten by larger fish and ocean animals.

“It could make it harder and harder for migratory species to time their life cycles to be in the Arctic when the bloom is at its peak,” Arrigo says. “If their food supply is coming earlier, they might be missing the boat.”

The research is published this week in Science.

Image: NASA