Climate 411

Global anthropogenic climate impacts must include nitrous oxide emissions from rice fields

By Kritee / Bio / Published: September 10, 2018

This blog was co-authored by Kritee, Jeremy Proville, Terry Loecke, Richie Ahuja

Rice is a critical global crop: it provides livelihood to 150 million households and is a staple for half of humanity. However, it uses 11% of arable land and a third of irrigation water. In addition, continuously flooded rice fields are like wetlands and known to produce about 12% of total anthropogenic methane (CH₄), a powerful short-lived greenhouse gas. Despite being one of the few crops whose climate impacts have been deeply studied over two decades, the potential of large emissions of nitrous oxide (N₂O), a long-lived greenhouse gas, from rice cultivation was surprisingly missed until recently.

Given that the United Nations Framework Convention on Climate Change (UNFCCC) negotiators working on agricultural mitigation are set to review the issue of water and nitrogen management in early 2019, it is crucial that the climate impacts of rice cultivation are determined and lowered over both the long- and short-term.

Photo by Rakesh Tiwari: Women harvesting seedlings for rice nursery

Posted in Agriculture, Greenhouse Gas Emissions, Science / Comments are closed

Global climate change can make fish consumption more dangerous

By Kritee / Bio / Published: December 4, 2013

Hundreds of thousands of babies are born in the U.S each year with enough mercury in their blood to impair healthy brain development. As they grow, these children’s capacity to see, hear, move, feel, learn and respond can be severely compromised. Why does this happen? Mostly because a portion of mercury emitted from local power plants and other global anthropogenic sources is converted to methylmercury, a neurotoxic and organic form of mercury that accumulates in fish.

In addition to poisoning human diet, mercury continues to poison the Arctic. Despite a lack of major industrial sources of mercury within the Arctic, methylmercury concentrations have reached toxic levels in many arctic species including polar bears, whales, and dolphins because of anthropogenic emissions at lower latitudes.

Relationship between mercury exposure and climate change: In its latest report to policymakers, the International Governmental Panel on Climate Change (IPCC) has made it clear that climate change and local high temperatures will worsen air pollution by increasing concentrations of ozone and PM2.5 in many regions. However, no scientific body has collectively assessed the potential impact of changing climate on mercury, a dangerous pollutant that contaminates not just our air but our soils and waters (and as a result human and wildlife’s food supply).

After attending this summer’s International Conference on Mercury as a Global Pollutant (ICMGP) in Edinburgh (Scotland), I don’t have good news. In the past few months, I have talked to several leading scientists who do research on different aspects on mercury cycle and they all seemed to agree with many recently presented and published peer-reviewed studies (see a selected list below): Climate change can significantly worsen mercury pollution. Even if global anthropogenic emission rate of mercury was to somehow be made constant, climate change can make fish-eating more dangerous because of the following:

Enhanced inorganic mercury release into waters — A combination of the following climate-related factors can lead to the release of higher amounts of mercury into waters:

Climate change (i.e., increased local precipitation under warmer conditions) will cause more local direct deposition of the emitted inorganic mercury on our lakes and ocean as compared to deposition under colder and dryer conditions.
Run-off (i.e., flow of mercury over land in a watershed that drains into one water body) an indirect but primary means by which mercury enters our local waters, will also increase under warmer and wetter conditions.
Extreme events (storms, hurricanes, forest-fires, tornadoes and alternating wetting-drying cycles) will cause erosive mobilization of inorganic mercury and organic matter in soils and release it into coastal and open waters where it can get methylated.
Thawing of the enormous areas of northern frozen peatlands may release globally significant amounts of long-stored mercury and organic matter into lakes (including those in the Arctic), rivers and ocean.

Enhanced Methylmercury production from inorganic mercury: In addition to increased release on inorganic mercury into the waters, the inorganic mercury might also have higher chances of getting converted to methylmercury.

In the open ocean, methylmercury is produced in regions known as “oxygen minimum zones”. Increased carbon dioxide concentrations in the atmosphere will cause higher primary productivity which will widen the existing ocean’s oxygen deficient zones leading to enhanced production of methylmercury.
Continued melting of permafrost will release organic matter which naturally contains high concentration of aromatic structures (structures similar to benzene rings). These kinds of organic matter have been shown to enhance the production rate of methylmercury.

Enhanced methylmercury bioaccumulation in the fish:

For a given amount of methylmercury in the water, there are various factors that control the concentration and bioaccumulation of methylmercury in the food chain. In a given water body, bigger fishaccumulate more methylmercury than smaller fish. Because of climate change, oceanic temperatures will be higher and higher temperatures have been shown to increase the metabolic growth rate and size of fish. Therefore, for a given amount of inorganic mercury emitted in the atmosphere or water, more methylmercury will accumulate in the fish (consequently, increase human exposure to methylmercury) as climate change becomes more severe.

These research results combined with the recent reports on higher genetic susceptibility of some people to mercury poisoning suggest that in order to protect human and wildlife health from negative effects of methylmercury exposure it is essential to swiftly enact and implement stringent laws to reduce both global mercury and greenhouse emissions from all major sources including coal power plants.

Governments across the globe now recognize that mercury is an extremely toxic metal that harms health of millions of children and adults every year and have moved forward with an international treaty to address this toxic pollution, called the Minamata convention. The Minamata convention was recently opened for signatures after 4 years of negotiations. The treaty will come into effect as soon as the 50th nation ratifies it. It has already been signed by 93 nation-states. I am happy to note that United States has been the first nation to ratify the treaty. We await , however, ratification from 49 more countries before the treaty can go into effect.

As an organization, EDF has been educating consumers and seafood businesses about mercury in seafood via our EDF Seafood Selector by doing quantitative Synthesis of Mercury in Commercial Seafood for many years. We also have expertise on the scientific, legal, and stakeholder processes that laid the groundwork for implementation of Mercury and Air Toxics Standards in the U.S; the health and economic implications of these emission standards; and the current state of technology available to reduce emissions from power plants in the U.S.

Thanks to your strong support, the U.S. has taken action to reduce mercury from power plants, the largest domestic source of mercury pollution. While many power plant companies are moving forward with investments to reduce mercury pollution, we need you to continue making your voices heard because the mercury standards (MATS) are still being challenged in the court from time to time.

References

Kathryn R. Mahaffey, Robert P. Clickner, and Rebecca A. Jeffries (2009) Adult Women’s Blood Mercury Concentrations Vary Regionally in the United States: Association with Patterns of Fish Consumption (NHANES 1999–2004) Environ Health Perspect. 117(1): 47–53.
Goacher, W. James and Brian Branfireun (2013). Evidence of millennial trends in mercury deposition in pristine peat geochronologies. Presented at the 11th International Conference on Mercury as a Global Pollutant; Edinburgh, Scotland.
Dijkstra JA, Buckman KL, Ward D, Evans DW, Dionne M, et al. (2013) Experimental and Natural Warming Elevates Mercury Concentrations in Estuarine Fish. PLoS ONE 8(3): e58401. doi:10.1371/journal.pone.0058401
Webster, Jackson P. et al. (2013) The Effect of Historical and Recent Wildfires on Soil-Mercury Distribution and Mobilization at Mesa Verde National Park, Colorado, USA. Presented at the 11th International Conference on Mercury as a Global Pollutant; Edinburgh, Scotland.
Blum et al (2013) Methylmercury production below the mixed layer in the North Pacific Ocean Nature Geoscience 6, 879–884
Stramma, Lothar (2010) “Ocean oxygen minima expansions and their biological impacts,” Deep Sea Research Part I: Oceanographic Research Papers. 57: 587–595
Bjorn, Erik et al. (2013) Impact of Nutrient and Humic Matter Loadings on Methylmercury Formation and Bioaccumulation in Estuarine Ecosystems. Presented at the 11th International Conference on Mercury as a Global Pollutant; Edinburgh, Scotland.
Bedowski, Jacek et al. (2013) Mercury in the coastal zone of Southern Baltic Sea as a function of changing climate: preliminary results. Presented at the 11th International Conference on Mercury as a Global Pollutant; Edinburgh, Scotland.
Grandjean, Philippe, et al. (2013) Genetic vulnerability to MeHg. Presented at the 11th International Conference on Mercury as a Global Pollutant; Edinburgh, Scotland.
Qureshi et al (2013): Impacts of Ecosystem Change on Mercury Bioaccumulation in a Coastal-Marine Food Web presented at the 11th International Conference on Mercury as a Global Pollutant; Edinburgh, Scotland.

Posted in Health, Policy, Science / Read 2 Responses

Protecting the Planet: A Report from the International Conference on Mercury in Edinburgh

By Kritee / Bio / Published: July 31, 2013

(EDF’s Mandy Warner co-wrote this post)

This week, experts in science, policy, and industry are meeting in Edinburgh, Scotland at the International Conference on Mercury as a Global Pollutant (ICMGP).

We are honored to join them to discuss international mercury science and policy, and to share EDF’s work on mercury.

The ICMGP has been held periodically for more than 18 years. It has become the pre-eminent international forum for formal presentation and discussion of scientific advances concerning mercury, and gathers between 700 and 1200 experts for the five-day conference and exhibition.

This year’s conference will be of particular importance, because this year will launch the United Nations Environment Programme (UNEP) Global Legally Binding Treaty on Mercury — which can provide much-needed global action on mercury.

This year, UNEP has also released its new report, Global Mercury Assessment 2013 – Sources, Emissions, Releases and Environmental Transport.

So this year’s meeting is perfectly timed to celebrate the release of the report AND the launch of the international treaty — and most important, to discuss how to put the treaty into practice. It will be a great opportunity for policymakers and scientists to collaborate on solutions that address worldwide mercury emissions.

It is well-known that mercury is an extremely toxic metal.

Mercury primarily exists in three chemical forms in nature: elemental mercury, oxidized mercury and methylmercury.

Methylmercury is the most neurotoxic substance that builds up collects in our aquatic foodchains.

About 400,000 children are born in the U.S. each year with so much mercury in their blood that healthy brain development is threatened.

As they grow, these children’s capacity to see, hear, move, feel, learn and respond is compromised.

While some forms of mercury are deposited near the emissions source, other forms — such as gaseous mercury — are stable in the atmosphere for approximately a year. Gaseous mercury can be deposited far from its source, even thousands of miles away – which is why it has global impacts.

The U.S. is leading the way to reduce mercury emissions from a variety of sources, including coal-fired power plants — the largest remaining source of mercury in America.

The Mercury and Air Toxics Standards for power plants are in place thanks in part to strong support from EDF members, and from our partners in the environmental, health, faith, environmental justice, and business communities.

Power companies are working now to meet emission standards by spring 2015, by installing American-made technology.

EDF has helped advance mercury policy at the state and national level in the U.S. over the past several decades.

During the development of the recently finalized Mercury and Air Toxics Standards, we provided technical comments and testimony; worked with EPA, states, companies; collaborated with both Republicans and Democrats in Congress to defend protective standards; and worked through the courts to advance strong mercury standards.

Our partner organizations like Moms Clean Air Force have helped engage diverse voices from across America, and bring new constituencies to the forefront of the national policy discussion on air pollution and toxics.

We now have the privilege of highlighting the U.S. experience reducing mercury and advancing technology solutions in the power sector to this important international scientific and policy forum.

We hope to forge new partnerships to advance an international solution to mercury pollution that can protect the health not only of Americans, but people across the globe.

Posted in Health, International, Policy, Science / Comments are closed

America’s Leading Mercury Scientists Call for Strong Air Pollution Standards

By Kritee / Bio / Published: December 14, 2011

The U.S. Environmental Protection Agency is expected to announce its long-awaited Mercury and Air Toxics Standards any day now.

The new standards would place the first-ever national limits on mercury and other toxic air pollution from coal- and oil-fired power plants, and the issue is already being examined from every possible angle – politics, economics, business, health, you name it.

Now a new group is weighing in.

Just yesterday, 23 of the country’s leading scientific experts on mercury wrote a letter to the White House about the proposed new standard and its importance to the health and safety of all Americans. And I had the honor of joining them!

Together, our group of scientists represents at least a million hours of study on mercury and its effects. But this is the first time we’ve publicly weighed in, as a group, to support this vitally important standard.

We felt compelled to write to President because, during recent Congressional hearings – despite voluminous scientific literature to the contrary – a few people actually claimed that there is no science to back up the health benefits of decreasing pollution from power plants.

Our letter is our answer to that ridiculous claim:

As mercury scientists and physicians, we strongly refute such statements

And we:

… affirm our belief that the Mercury and Air Toxics Standards (MATS) will protect the health of thousands of Americans each year.

Some of us have studied how mercury travels in our air, soils or waters — and how it ends up in our bodies. Some of us specialize in how various forms of mercury affect everything from our individual enzymes and cells all the way to our ecosystems. We have, collectively, traced mercury all the way from smokestacks to the cells in our bodies. We also represent physicians who actually treat patients, including children, who have chronic pulmonary, cardiovascular, and neurological diseases caused by air pollution.

And we all came to the same conclusion, which we put into our letter:

… minimizing all mercury exposure is essential to improving human, wildlife and ecosystem health because exposure to mercury in any form places a heavy burden on the biochemical machinery within cells of all living organisms.

Our letter both affirms our support for the scientific findings of EPA’s Science Advisory Board on the health impacts of methylmercury, and goes a step further – to highlight the toxicity of all forms of mercury.

Here are our key points:

The neurological development, particularly brain maturation, of fetus and young children are severely affected by methylmercury, the form of mercury that collects and concentrates in aquatic food chains.
While the neurotoxicity of methylmercury to the young has been widely acknowledged, the effects on children and adults through exposure to all other forms of mercury have not been effectively publicized. No form is mercury is safe.
Mercury has no biologically beneficial function; indeed, each atom that ends up in the body can be toxic to all types of cells.
Mercury is such a potent toxin because it bonds very strongly to functionally important sites of proteins including enzymes, antibodies and nerve growth-cones that keep cells alive, “intelligent” and safe.

One of my personal heroes is the late Dr. Kathryn R. Mahaffey, who conducted careful studies for over a decade to test the mercury levels in the blood of women of child bearing age in the U.S. Her research is the reason we know that about 10 percent of babies born in America each year have mercury levels sufficient to cause adverse neurological and developmental health effects. Along with her collaborators, she also carefully compiled information on the effects of all forms of mercury on our endocrine system, including hormones that control functioning of our reproductive system.

The pioneering research tools and methodologies developed by several of the mercury research giants who have signed on to this letter helped Dr. Mahaffey reach her conclusions. Some of the signatories are now building on Dr. Mahaffey’s work in insightful ways. For example, Dr. Chad Hammerschmidt from Wright State University has written that unless we decouple mercury emission from power production, we could have as many as 30 percent of children born in the U.S with too much mercury in their blood. Along with their collaborators, Drs. David Evers, Charlie Driscoll and Thomas Holsen identified that local mercury emissions are linked to such high mercury concentrations in multiple biological species that these areas of high mercury emissions were referred to as biological mercury hotspots.

I would love to write more about the fundamental ways in which the signatories of this letter have added to the understanding of the transport, transformations and toxicity of mercury, and I encourage you read the entire letter to see who they are, and to learn more about the work they do.

We fully understand the remaining uncertainties in our understanding of the global mercury cycle. Yet we believe there is irrefutable proof for:

The local and regional deposition of mercury from coal-fired power plants within the U.S.
The toxicity of each and every atom of mercury in any form, and
Rapid reductions in mercury levels in many biological species upon reductions in mercury emissions from local sources

Thus, we attest to the wisdom of stringent national-level mercury regulation. Now we need our policy makers to act. We need them to create and support a strong Mercury and Air Toxics Standards.

Posted in Clean Air Act, Health, News, Policy, Science / Read 2 Responses