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It’s a Moment of Reckoning For How We Use the Planet to Halt Climate Change, Warns U.N. Report  

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Aerial view of the Transamazonica Road (BR-230) near Medicilandia, Para State, Brazil on March 13, 2019. – According to the NGO Imazon, deforestation in the Amazonia increased in a 54% in January, 2019 -the first month of Brazilian President Jair Bolsonaro’s term- compared to the same month of 2018. MAURO PIMENTEL—AFP/Getty Images

The human relationship with the land we live on has evolved over the hundreds of thousands of years humans have roamed the planet, but no period has seen as dramatic change as the last century when humans used land in new ways to extract wealth and build a modern economy.

Now, a landmark new U.N. report warns, humans face a moment of reckoning on how we use the planet’s land: human practices like deforestation threaten to undermine the role nature has played soaking up carbon dioxide emissions for more than a century. At the same time, climate change could threaten our ability to use the land, risking food security and vulnerable communities at risk of extreme weather.

“As we’ve continued to pour more and more carbon dioxide in the atmosphere, the Earth’s system has responded and it’s continued to absorb more and more,” says Louis Verchot, a lead study author and scientist at the International Center for Tropical Agriculture. But “this additional gift from nature is limited. It’s not going to continue forever.”

Today, emissions from land use — think of practices like agriculture and logging — cause nearly a quarter of human induced greenhouse emissions, according to the report, authored by scientists on the Intergovernmental Panel on Climate Change (IPCC), the U.N. climate science body.

Still, land elsewhere on the planet has balanced the effects of those emissions. In recent years, forests, wetlands and other land systems have soaked up 11.2 gigatonnes more carbon dioxide than they have emitted on an annual basis. That’s a greater quantity of carbon dioxide than released by the world’s coal-fired power plants in a given year. But a slew of human practices including deforestation, soil degradation and the destruction of land-based ecosystems threaten to halt that trend, potentially driving land to release more carbon dioxide than it absorbs.

Climate advocates billed the report as a wakeup call. Much of the attention around addressing climate change has focused on shifting the global energy system, but to keep warming at bay will require nature-based solutions that consider how humans use land, climate scientists say.

The report — at more than 1,300 pages in length — lays out a number of opportunties to use land to reverse the trend. And many of the solutions are already at hand, if governments have the wherewithal to implement them. “We don’t have to wait for some sort of new technological innovation,” says study author Pamela McElwee, an associate professor of human ecology at Rutgers University. “But what some of these solutions do require is attention, financial support, enabling environments.”

Significantly reducing deforestation while increasing the rates of restoring forests ranks among the most urgent solutions in order to retain any hope of keeping temperatures from rising to catastrophic levels by the end of the century. Reducing deforestation alone can stop annual emissions equivalent to twice those of India’s, scientists found.

The report also highlights how emissions from agriculture contribute significantly to climate change, and the opportunity to address it by rethinking diets. As global demand for food has grown, food producers have converted forests into agricultural land, leading to a release of carbon dioxide stored in trees. At the same time, more than a quarter of food goes to waste, according to the report.

With those trends in mind, scientists say a shift away from eating meat toward plant-based diets could yield big dividends in the fight against climate change. Reduced meat consumption means lower emissions from livestock and the fertilizer needed to sustain them but also provides an opportunity to reforest land that farmers would have otherwise used for grazing. Rethinking the human diet across the globe could drive emissions reductions of up to 8 gigatonnes annually, according to the report, greater than an entire year of emissions in the U.S.

But, while these changes are technically feasible, there are a number of barriers to adoption. To achieve the greatest emissions reductions by shifting diets would require most of the world to go vegan, for instance, requiring a fight against entrenched agricultural interests and cultural preferences.

And despite year’s of research underscoring the threat of deforestation the practice has worsened in some of the most critical areas. In recent years, deforestation has accelerated in the Amazon rain forest in both Brazil and Colombia, with a recent report from Brazil’s National Institute for Space Research showing that the practice had increased 40% in the previous two months compared with the same period the year prior.

The new IPCC report comes less than a year after the body’s 2018 report on the dire effects of 1.5°C of warming, which warned that climate change will bring catastrophic levels at even that level of warming. In its wake, students walked out of school across the globe, some governments committed to reducing their emissions and activists in the U.S rallied for a Green New Deal, all citing the report’s impact.

Much like last year’s, the new IPCC report highlights a number of shocking risks. The surface temperature on land has already warmed more than 1.5°C since the beginning of the industrial era, and continued warming threatens to cause a slew of extreme weather events while threatening food security and other essentials required for human life. Whether this report can inspire a similar wave of action remains to be seen.

By Justin Worland

Source: It’s a Moment of Reckoning For How We Use the Planet to Halt Climate Change, Warns U.N. Report  

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Climate Change & Overfishing Are Increasing Toxic Mercury Levels In Fish Study Says

Mercury levels in the seafood supply are on the rise, and climate change and overfishing are partially to blame, according to a new study. Scientists said mercury levels in the oceans have fallen since the late 1990s, but levels in popular fish such as tuna, salmon and swordfish are on the rise.

According to a new study by Harvard University researchers in the journal Nature, some fish are adapting to overfishing of small herring and sardines by changing their diets to consume species with higher mercury levels.

Based on 30 years of data, methylmercury concentrations in Atlantic cod increased by up to 23% between the 1970s and the 2000s. It links the increase to a diet change necessitated by overfishing.

But overfishing isn’t the only contributor to higher mercury levels in fish. Climate change — and the rising ocean temperatures that come with it — means fish are more active and need more food to survive. Consuming more prey means consuming more mercury.

But overfishing isn’t the only contributor to higher mercury levels in fish. Climate change — and the rising ocean temperatures that come with it — means fish are more active and need more food to survive. Consuming more prey means consuming more mercury.

The study also found that mercury levels in Atlantic bluefin tuna have increased by an estimated 56% due to seawater temperature rise since 1969.

Climate change “is not just about what the weather is like in 10 years,” said lead researcher Amina Schartup. “It’s also about what’s on your plate in the next five.”

Scientists said human exposure to methylmercury — the compound created when mercury enters the ocean — is especially risky for pregnant women, as it has been linked to long-term neurological disorders when fetuses are exposed in the womb. It is considered a major public health concern by the World Health Organization.

“It’s not that everyone should be terrified after reading our paper and stop eating seafood, which is a very healthy, nutritious food,” senior author Elsie Sunderland told Reuters. “We wanted to show people that climate change can have a direct impact on what you’re eating today, that these things can affect your health … not just things like severe weather and flooding and sea level rise.”

Since the late 1990s, mercury concentrations have declined overall following increased regulations and decreased coal-burning power plants. In 2017, a global treaty was introduced to reduce mercury emissions.

But mercury levels in fish have not fallen as expected. The treaty failed to account for overfishing’s massive effects on marine ecosystems or climate change’s impact on the diets of fish. So, much of our current seafood supply actually contains more mercury than before.

The study also found that mercury levels in Atlantic bluefin tuna have increased by an estimated 56% due to seawater temperature rise since 1969.Climate change “is not just about what the weather is like in 10 years,” said lead researcher Amina Schartup. “It’s also about what’s on your plate in the next five.”

Scientists said human exposure to methylmercury — the compound created when mercury enters the ocean — is especially risky for pregnant women, as it has been linked to long-term neurological disorders when fetuses are exposed in the womb. It is considered a major public health concern by the World Health Organization.

“It’s not that everyone should be terrified after reading our paper and stop eating seafood, which is a very healthy, nutritious food,” senior author Elsie Sunderland told Reuters. “We wanted to show people that climate change can have a direct impact on what you’re eating today, that these things can affect your health … not just things like severe weather and flooding and sea level rise.”

Since the late 1990s, mercury concentrations have declined overall following increased regulations and decreased coal-burning power plants. In 2017, a global treaty was introduced to reduce mercury emissions.

But mercury levels in fish have not fallen as expected. The treaty failed to account for overfishing’s massive effects on marine ecosystems or climate change’s impact on the diets of fish. So, much of our current seafood supply actually contains more mercury than before.

According to a recent report by Australian climate experts, the world’s oceans will likely lose about one-sixth of its fish and other marine life by the end of the century if climate change continues on its current path. If the world’s greenhouse gas emissions stay at the present rate, that means a 17% loss of biomass — the total weight of all marine animal life — by the year 2100. But if the world reduces carbon pollution, losses can be limited to only about 5%, the study said.

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But our regulations against mercury pollution could be weakening under the Trump administration. In December, the Environmental Protection Agency targeted an Obama-era regulation credited with helping dramatically reduce toxic mercury pollution from coal-fired power plants.

In the U.S. coal power plants are the largest single manmade source of mercury pollutants. As coal combustion emits mercury into the atmosphere, the ocean absorbs it, converting it into methylmercury. The EPA proposal argued that savings for companies were greater than any increased perils to safety or the environment.

The carbon we release into the atmosphere has a direct correlation to the toxins that end up in our food supply.

Methylmercury levels increase when an animal eats its prey — accumulating in larger doses as it goes through the food chain. So when a human consumes tuna, for example, it is also consuming all of the mercury consumed by its prey, all the way down the food chain.

According to the study, about 80% of exposure to Methylmercury in the U.S. comes from seafood, and 40% from tuna alone. Scientists said stronger regulations are needed for greenhouse gases and mercury emissions in order to keep our fish supply healthy and thriving.

By Sophie Lewis

Source: Climate change and overfishing are increasing toxic mercury levels in fish, study says

 

 

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