Radiation levels in the Pacific Ocean are almost back to pre-Fukushima levels

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Radiation levels in the Pacific Ocean are almost back to pre-Fukushima levels

Yay?

The wounds left by the 2011 earthquake and subsequent tsunami off the coast of Japan are taking a long time to heal, but there's some positive news from scientists measuring radiation levels in the Pacific Ocean.

After more than five years, those levels are almost back down to normal, even as radioactive material continues to leak out of the Fukushima Daiichi nuclear power plant that was damaged in the tsunami.

Scientists from Edith Cowan University (ECU) in Australia led an international team in a major review of radiation levels right across the Pacific, to check the status of the water five years after the disaster. According to the researchers, there's good news and bad news.

"Radiation levels across the ocean are likely to return to levels associated with background nuclear weapon testing over the next four to five years," said review co-author Pere Masqué from ECU. "However, the seafloor and harbour near the Fukushima plant are still highly contaminated, and monitoring of radioactivity levels and sea life in that area must continue."

To give some context, back in 2011, around half the fish samples taken from coastal waters off Fukushima were found to contain unsafe levels of radioactive material. By last year, that number had dropped to just 1 percent.

The 2011 event resulted in the largest ever leak of radioactive material into the world's oceans, and the incident is one of only two to qualify as a level 7 event on the International Nuclear Event Scale (along with Chernobyl). As such, the scale of the terrible episode makes the news that the Pacific Ocean is now recovering all the more incredible. 

To check radioactivity levels in the Pacific, the researchers incorporated 20 individual studies, analysing levels of radioactive caesium detected in the ocean from Japan’s coast across to North America.

Caesium is a particularly useful chemical element for tracking the dispersal of radiation, because it's a byproduct of nuclear power and is highly soluble in water.

Credit: Annual Review of Marine Science

Despite the promising drop in radioactivity, the researchers are calling for more support to be put behind monitoring efforts, as dangerous materials continue to leak out of the Fukushima plant.

Efforts to curb that leakage are also ongoing: an underground frozen wall is one of the ways Japanese authorities are looking to minimise the amount of radioactive material that seeps out in the future, but it's going to take an estimated 30 to 40 years before the plant is fully decommissioned.

"Although one cannot expect a total return of the communities to their status [as it was] before March 11, 2011," write the scientists in their final report, "it is hoped that, with time, a new normality will return to the affected areas and that an improved understanding of the fate and impacts of radionuclides discharged to the oceans will help to contribute to that recovery."

The findings have been published in the Annual Review of Marine Science.

We've missed our chance to seriously stop climate change, study finds

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We've missed our chance to seriously stop 
climate change, study finds

:(

We've passed the point of no return when it comes to stopping a rise of 1.5°C in global temperatures, a new study has found. That 1.5°C figure was a 'stretch goal' set down by the countries who signed up to the Paris agreement last December, but we've already well and truly missed the mark.

Now the race is on to limit the damage in rising temperatures to 2°C globally through a switch from fossil fuels to renewable energy sources, but the signs aren't looking great on that front either.

Researchers led by a team from the International Institute for Applied Systems Analysis ((IIASA) in Austria looked at the pledges submitted by the 195 countries who signed up to the Paris agreement in 2015, and calculated the level of global warming they're likely to lead to.

It looks like we're on course for a 2.6 to 3.1°C rise in temperature by the end of the century, they've concluded, if the reductions planned between now and 2030 are continued over the next 70 years.

The hopes of limiting temperature rise to 1.5°C by 2100 appear to have already disappeared, while the 2°C threshold is als under threat if countries don't promise to cut back on their carbon use even further.

"To go the rest of the way, we would need to assume much more stringent action after 2030, which leads to emissions reductions of about 3 to 4 percent per year globally," explained one of the team, Niklas Höhne from Wageningen University in the Netherlands.

"But in practice, switching to such stringent reductions right after 2030 would be challenging, and require time," he added. "[T]hat means that in order to ensure a chance of meeting these targets, we need significant further action from countries before 2030."

Let's hope the report acts as a warning call. As Gizmodo's Maddie Stone points out, a 3°C rise in temperatures would equal around a 6-metre (20-foot) rise in sea levels over several centuries, leaving hundreds of millions of people having to move home.

Low-lying nations were responsible for ensuring that the 1.5°C figure was included in the Paris agreement, but it looks like their hopes of hitting that target are now dashed. In fact, we might reach it as early as 2017, let alone keeping it at bay until 2100.

The Paris agreement does state that countries should improve their targets over time from 2020, but the new paper says these improvements are going to have to be "substantial" to avoid a rise of more than 2°C.

The team behind the study has also called on countries to be more specific about their emission targets in the coming years, finding that the range of uncertainties in the agreement as it stands adds up to approximately 6 billion tonnes of CO2 - that's the entire amount of carbon emitted by the US in 2012.

We need to take drastic action now - or face the consequences.

The findings have been published in Nature.

The ozone hole is finally closing up

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The ozone hole is finally closing up

We didn't ruin *everything*.

Scientists have found evidence that the hole in the ozone layer over Antarctica is finally beginning to heal. If progress continues, it should be closed permanently by 2050.

The news comes almost 30 years since the world worked together to phase out ozone-depleting chemicals, so we're allowed to give ourselves a little pat on the back. "We can now be confident that the things we’ve done have put the planet on a path to heal," said lead researcher Susan Solomon from MIT.

In the '80s and '90s, the hole in the ozone layer was the environmental threat that everyone was worried about. After decades of pumpingchlorofluorocarbons (CFCs) into the atmosphere - through dry cleaning, aerosols, and old refrigerators - scientists found that the ozone over Antarctica had become seriously thin.

That's not great, seeing as the ozone layer is the shield that absorbs much of the Sun's harmful UV rays before they reach Earth.

To combat the problem, most countries on the planet signed the Montreal Protocol in 1987, which was a global treaty that governed the gradual phase-out of CFCs and other ozone-damaging chemicals.

And now researchers using new longitudinal measurements have shown that the hole is finally starting to heal, and has shrunk by 4 million square kilometres since its peak in 2000. That's roughly half the size of the mainland US.

It did expand to a record size in 2015 due to the eruption of the Chilean volcano, Calbuco, but if environmental progress continues, the hole should be fully closed by mid-century.

"Which is pretty good for us, isn’t it?" said Solomon. "Aren’t we amazing humans, that we did something that created a situation that we decided collectively, as a world, 'Let’s get rid of these molecules'? We got rid of them, and now we’re seeing the planet respond."

Since scientists first started noticing that the ozone hole was getting bigger inthe mid-1980s, they've been monitoring ozone levels every year in October, when Antarctica moves out of its long winter months and gets sunnier - because chlorine only eats away at ozone when light and cold winds are present.

But the ozone hole starts opening up in August, and Solomon and her team thought they might get more accurate measurements if they tested levels in September, when the temperatures are still cold.

The team was able to show that as chlorine levels in the atmosphere decreased, the rate at which the ozone hole opens up has slowed. 

"I think people, myself included, had been too focused on October, because that’s when the ozone hole is enormous, in its full glory," said Solomon. "But October is also subject to the slings and arrows of other things that vary, like slight changes in meteorology. September is a better time to look because chlorine chemistry is firmly in control of the rate at which the hole forms at that time of year. that point hasn’t really been made strongly in the past."

In addition to monitoring the September ozone levels from 2000 to 2015, the team measured the amount of sulphur dioxide emitted by volcanoes each year, which can add to ozone deterioration. They also compared their results with model simulations that predict ozone levels based on the amount of chlorine in the atmosphere each year. 

They found that not only did their observations show that the hole was shrinking, it also matched the model's predictions, suggesting that more than half of the change had been driven by the decreasing chlorine in the atmosphere.

"It showed we can actually see a chemical fingerprint, which is sensitive to the levels of chlorine, finally emerging as a sign of recovery," said one of the researchers, Diane Ivy.

The research, which has been published in Science, also shows that we can actually fix some of the damage we've done to the environment when we work together. 

"This is a reminder that when the world gets together, we really can solve environmental problems," Solomon told Gizmodo. "I think we should all congratulate ourselves on a job well done."