Tyler O'Neal, Staff Editor

Satellites large datasets are key to understanding ocean carbon in climate change

Satellites now play a key role in monitoring carbon levels in the oceans, but we are only just beginning to understand their full potential.

Our ability to predict future climate relies upon being able to monitor where our carbon emissions go. So we need to know how much stays in the atmosphere, or becomes stored in the oceans or on land. The oceans, in particular, have helped to slow climate change as they absorb and then store the carbon for thousands of years.

The IPCC Special Report on the Oceans and Cryosphere in a Changing Climate, published in September, identified this critical role that the ocean play in regulating our climate along with the need to increase our monitoring and understanding of ocean health.

But the vast nature of the oceans, covering over 70% of the Earth's surface, illustrates why satellites are an important component of any monitoring. CAPTION This is Tonga from space. CREDIT Copernicus Sentinel data processed by ESA{module In-article}

The new study, led by the University of Exeter, says that increased exploitation of existing satellites will enable us to fill "critical knowledge gaps" for monitoring our climate.

The work reports that satellites originally launched to study the wind, also have the capability to observe how rain, wind, waves, foam, and temperature all combine to control the movement of heat and carbon dioxide between the ocean and the atmosphere.

Additionally, satellites launched to monitor gas emissions over the land are also able to measure carbon dioxide emissions as they disperse over the ocean.

Future satellite missions offer even greater potential for new knowledge, including the ability to study the internal circulation of the oceans. New constellations of commercial satellites, designed to monitor the weather and life on land, are also capable of helping to monitor ocean health.

"Monitoring carbon uptake by the oceans is now critical to understand our climate and for ensuring the future health of the animals that live there," said lead author Dr. Jamie Shutler, of the Centre for Geography and Environmental Science on Exeter's Penryn Campus in Cornwall.

"By monitoring the oceans we can gather the necessary information to help protect ecosystems at risk and motivate societal shifts towards cutting carbon emissions."

The research team included multiple European research institutes and universities, the US National Oceanic and Atmospheric Administration, the Japan Aerospace Exploration Agency and the European Space Agency.

The researchers call for a "robust network" that can routinely observe the oceans.

This network would need to combine big data from many different satellites with information from automated instruments on ships, autonomous vehicles, and floats that can routinely measure surface water carbon dioxide.

And recent supercomputing advancements, such as Google Earth Engine, which provides free access and supercomputing for scientific analysis of satellite datasets, could also be used. CAPTION This is the Aeolus liftoff. CREDIT ESA, S Corvaja

The study suggests that an international charter that makes satellite data freely available during major disasters should be expanded to include the "long-term man-made climate disaster", enabling commercial satellite operators to easily contribute.

The research was supported by the International Space Science Institute ISSI Bern, Switzerland, and initiated by Dr. Shutler at the University of Exeter and Dr. Craig Donlon at the European Space Agency.

The paper, published this week in Frontiers in Ecology and Environment, is entitled: "Satellites will address critical science priorities for quantifying ocean carbon."

Cornell scientists use AI to help reduce Amazon hydropower dams' carbon footprint

Tyler O'Neal, Staff Editor

A team of scientists has developed a computational model that uses artificial intelligence to find sites for hydropower dams in order to help reduce greenhouse gas emissions.

Hydropower dams can provide large quantities of energy with carbon footprints as low as sources like solar and wind. But because of how they're formed, some dams emit dangerously high levels of greenhouse gases, threatening sustainability goals.

With hundreds of hydropower dams currently proposed for the Amazon basin - an ecologically sensitive area covering more than a third of South America - predicting their greenhouse emissions in advance could be critical for the region, and the planet. {module In-article}

The Cornell University-led team of ecologists, computer scientists and researchers from South American organizations found that achieving low-carbon hydropower requires planning that considers the entire Amazon basin - and favors dams at higher elevations.

"If you develop these dams one at a time without planning strategically - which is how they're usually developed - there is a very low chance that you'll end up with an optimal solution," said Rafael Almeida, postdoctoral research fellow with the Atkinson Center for a Sustainable Future and co-lead of "Reducing Greenhouse Gas Emissions of Amazon Hydropower with Strategic Dam Planning," which published Sept. 19 in Nature Communications.

Using the model, the researchers can identify the combination of dams that would produce the lowest amounts of greenhouse gases for a given energy output target.

When areas are flooded to build dams, decomposing plant matter produces methane, a more destructive greenhouse gas than carbon dioxide. Depending on the location and other factors, the carbon emissions from dam construction can vary from lowest to highest by more than two orders of magnitude.

The analysis found that dams built at high elevations tend to lower greenhouse gas emissions per unit of power output than dams in the lowlands - partly because less land needs to be flooded in steeper environments.

There are currently around 150 hydropower dams and another 350 proposed for the Amazon basin, which encompasses parts of Brazil, Ecuador, Peru and Bolivia. This study is part of a larger effort to use computational tools to analyze the dams' impact to help South American governments and organizations make informed decisions that balance the benefits and disadvantages.

Empirical energy consumption model quantifies Bitcoin's carbon footprint

Tyler O'Neal, Staff Editor

Researchers have conducted the first analysis of Bitcoin power consumption based on empirical data from IPO filings and localization of IP addresses. They found that the cryptocurrency's carbon emissions measure up to those of Kansas City--or a small nation. The study, published June 12 in the journal Joule, suggests that cryptocurrencies contribute to global carbon emissions, an issue that must be considered in climate change mitigation efforts.

Bitcoin and other cryptocurrencies rely on blockchain technology, which enables a secure network without relying on a third party. Instead, so-called Bitcoin "miners" guarantee a system without fraud by validating new transactions. Miners solve puzzles for numerical signatures, a process that requires enormous amounts of computational power. In return, miners receive Bitcoin currency.

"This process results in immense energy consumption, which translates into a significant carbon footprint," says Christian Stoll, a researcher at the Center for Energy Markets at the Technical University of Munich, Germany, and the MIT Center for Energy and Environmental Policy Research. {module In-article}

Scientists have growing concerns that Bitcoin mining is fueling an appetite for energy consumption that sometimes draws from questionable fuel sources--such as coal from Mongolia--in addition to hydropower and other low-carbon power resources. And cryptocurrency's energy issues seem to only be getting worse, with the computing power required to solve a Bitcoin puzzle increasing more than four-fold in 2018. While there is a growing push among researchers to quantify Bitcoin's energy consumption in order to better understand its contribution to global climate change, recent studies have struggled to generate accurate estimates.

"We argue that our work goes beyond prior work," says Stoll. "We can provide empirical evidence where current literature is based on assumptions."

Stoll and his team used IPO filings disclosed in 2018 by all major mining hardware producers to determine which machines miners are actually using and the power efficiencies of these machines. They also used IP addresses to determine emissions scenarios for actual mining locations and compare carbon emissions from power sources used by Bitcoin miners in different locations. Finally, they calculated Bitcoin's carbon footprint based on its total power consumption and estimates from different emissions scenarios. These include a lower limit scenario, in which all miners use the most efficient hardware; an upper limit scenario, in which miners behave rationally by disconnecting their hardware as soon as costs exceed revenue; and a best guess scenario, which accounts for the anticipated energy efficiency of the network and realistic additional energy losses from cooling and IT hardware.

"Our model reflects how the connected computing power and the difficulty of Bitcoin search puzzles interact, and it provides high precision of power consumption since it incorporates auxiliary losses," says Stoll. "However, the precision of our results strongly depends on the accuracy of the input data, such as the IPO filings for hardware characteristics. The carbon emissions strongly depend on the assumed carbon intensity of power consumption."

Using this model, Stoll and his team estimated Bitcoin's annual energy consumption at 45.8 terawatt hours. This allowed them to calculate an annual carbon emissions range between 22.0 and 22.9 megatons of CO2--equivalent to CO2 emitted by Kansas City and placing Bitcoin's emissions between Jordan and Sri Lanka in emissions rankings (the 82nd and 83rd highest emitters). However, the researchers estimate that the energy consumption estimate would almost double (greatly amplifying emissions estimates) if they were to include all other cryptocurrencies in their consequences.

"We do not question the efficiency gains that blockchain technology could, in certain cases, provide," says Stoll. "However, the current debate is focused on anticipated benefits, and more attention needs to be given to costs."