By Tiffany Chen, Dec. 11, 2017 –

Climate change is an urgent threat linked to floods, drought and increasing heat waves.  While carbon dioxide emissions continue to rise, President Donald Trump pulled the United States out of the Paris Climate Accord meant to cap emissions and the temperature rise due to them. Scientists gathered at the Comer Climate Change Conference in southwestern Wisconsin this fall to share their latest research and emphasize the critical need to fight climate change now.

Scientists agree that cutting back carbon dioxide emissions from fossil fuels and the investment in renewable energies might provide a solution. We have many alternative technologies already.

But one country can’t fight climate change on its own, it requires collaborations and communication among nations, scientist, law makers and the public.

PHOTO AT TOP: Climate change scientists gathered at the Comer Abrupt Climate Change Conference this fall to share their latest research and their deep concerns for the future ahead. (Tiffany Chen/MEDILL)

NOTE: Tiffany Chen is a Comer Scholar, a Medill Scholarship program supported by the Comer Family Foundation to promote graduate studies in science and environmental journalism



By Tiffany Chen

The oceans have always held carbon dioxide (CO2) in their vast blue depths during glacial and warm periods throughout Earth’s history, breathing it in and out as the climate warmed or cooled. Scientists are now fishing for clues from the floor of the sea to reconstruct past climate events via ocean chemistry to better understand what’s coming in the future.

The oceans have been absorbing humanity’s steadily increasing CO2 emissions since the start of the Industrial Revolution, buffering the impact of climate change. If not for the oceans, the Earth would be in far more trouble.

Indicators from deep sea sediments reflect the ocean’s storage of CO2. The total amount of carbon in the ocean is about 50 times greater than the atmosphere, and 48 percent of the carbon emitted into the atmosphere by burning fossil fuels resides in the sea, according to NASA.

“The CO2 level is 80 to 100 parts per million (pCO2) higher during ‘normal’ interglacial periods relative to glacials,” said Allison Jacobel, postdoctoral research assistant in Earth and Environmental Sciences at Columbia University.  “The question is, where did the CO2 go during glacial periods?” The leading hypothesis is that CO2 was stored in the ocean where gases dissolve. The atmosphere and ocean exchanges CO2 until an equilibrium is reached.

Atmosphere and ocean CO2 cycling pattern. (National Oceanic and Atmospheric Administration)

Jacobel studies uranium in seabed sediments. Uranium in the ocean is well-distributed and soluble, but when there’s a shortage of oxygen in marine sediments, uranium precipitates into a mineral form of reduced uranium and that’s how scientists know oxygen was lower and CO2 concentrations were higher in the ocean at a given time when the sediments were deposited.

Alison Jacobel of Columbia University

“It’s an indirect way to know [what] concentration of oxygen in the ocean was like,” said Jacobel, who preented her research at the Comer Abrupt Climate Change Conference this fall in southeastern Wisconsin. “We exhale CO2, and we take in oxygen, and so we sort of have an inverse relationship between how much oxygen there is and how much carbon there is.” Her studies suggest that the glacial carbon is stored in North Pacific deep water.

“We’re trying to explore how the Earth’s system works, how it behaves, what its natural variability is,” said Jerry McManus, professor of Earth and Environmental Sciences at Columbia University. “That won’t give us all the answers to what’s going on today, but it gives us a better understanding of the various interactions.”

McManus studies the accumulation of calcium carbonate (CaCO3), a crucial building block for organisms to form their shells in the ocean, and a climate change indicator. Calcium carbonate is part calcium and carbon and so it plays an important role in the carbon cycle of the Earth.

Calcium carbonate contributes to the ocean’s alkalinity, the ability of the ocean to neutralize acid. It is essential to the CO2 uptake of the ocean because the dissolved form of CO2 is acidic. “This property of the sea allows it to absorb a great deal of CO2,”  McManus said. “The calcium carbonate in solution is what holds CO2 from the atmosphere.”

Jerry McManus of Columbia University presents his latest reearch at the Comer Conference on the ocean’s uptake of carbon dioxide.

However, there is a catch.

Because the ocean has become more acidic since the industrial revolution, according to the Intergovernmental Panel on Climate Change (IPCC), the acidification causes more calcium carbonate to dissolve.This negatively impacts marine life with their shells made of calcium carbonate.. The warming and acidification of surface water also weakens the ocean’s ability to take up CO2 from the atmosphere.

“If we can determine natural variability, then we can determine whether [what] we’re doing now is really abnormal,” said Jacobel. “I think the consensus among scientists is that what we’re doing now has no parallel in Earth’s history.”

Photo at top: Ocean uptake of CO2 buffers the already high levels of the greenhouse gas in the atmosphere. (Medill photo)

Note: Tiffany Chen is a Comer Scholar, a Medill scholarship program supported by the Comer Family Foundation to promote graduate study of science and environmental journalism.


By Tiffany Chen –

 Drought and crop faiure in the Midwest. (Abigail Foerstner/Medill)

Water is a scarce resource to 1.1 billion people worldwide who lack access to water, according to World Wildlife Fund. And some 4 billion people suffer from water shortages for part of the year. Though water covers 70 percent of the planet’s surface, only 1 percent of it is drinkable.

When the quality, quantity, availability and accessibility of water is unreliable, researchers consider people and communities as water insecure. This complex risk is woven into our everyday life, impacting economic productivity, health and nutrition, according to scientists measuring the impact with the Household Water Insecurity Experiences (HWISE) scale.

Scientists from around the globe gathered to share potential solutions to worldwide water shortages during the Household Water Insecurity Experience Conference at Northwestern University

To tackle the problem, researchers gathered at Northwestern University to develop and refine the first household insecurity scale, a novel tool to meaure water insecurity that people face at the household level. Northwestern anthropologist Sera Young organized the  three-day HWISE conference in conjunction with the university’s Institute for Policy Research and Center for Water Research to draw together collaborators who have collected data from across the globe.

“Water insecurity is very important,” said Shalean Collins, research study coordinator for Young’s group at Northwestern, who explained the urgency of worldwide water issues. “Anywhere you go, people will tell you in many different contexts and in many different languages, ‘water is life.’”

“There is no one, true cross-culturally appropriate way to measure water insecurity at the level of the household,” said Collins. “Water is used for more than consumption. It’s used for economic productivity [and] for all manner of things. It’s harder to pin down exactly what water insecurity is and how to measure it.”

Water has numerous usages within a household. A family needs water to drink, to bathe and to water their crops. With shortages, families have to decide how to prioritize water use and consumption and distribute their resource accordingly. These choices can make it difficult for scientists to assess how severe water scarcity is in a region and how global warming is making scarcity worse.

The HWISE research spans four continents and 19 study sites, from South America to Asia. The mission of the project is to develop a systematic cross-cultural scale to measure household-level water insecurity, to track the changes in insecurity over time and evaluate the effectiveness of interventions.

“Across the sites where data has been collected, [we find that the length of questionnaires] needs to be reduced,” said Godfred Boateng, a postdoctoral reearcher with Young’s group who analyzes data from the field sites. “The goal [of this conference] is to do some content re-evaluation, take out the redundant questions and make sure we have questions and items that are relevant to the scale we are developing.”

“Forcing people to answer yes and no questions is not optimal,” said Professor Edward Frongillo, of the University of South Carolina. Scientists agreed that short and quantifiable questions should be asked to assess household-level water insecurity level in the community and to avoid respondent fatigue.

Researchers often face many difficulties collecting data in the field due to cultural differences and the interpretation of language.

“Upset” is often translated into “sad” or “angry” in African and Latin American countries. Colleagues at the conference suggested researchers optimize the questions by asking “how satisfied” people are with water supplies before prompting respondents to answer the full water insecurity scale.

In translating the scale into local languages, researchers have to ensure they don’t lose the meaning of their questions. They often need to paraphrase the questions until it is fully understood by respondents, said Patrick Mbullo, a graduate student at Northwestern University from Kenya.

Amber Pearson, assistant professor of geography, Michigan State University, participates in the HWISE workshop.

Social psychology also plays a role. When interviewers question if there is enough money to buy water, people are often offended because they think the researchers are implying they cannot provide for their family, said Mobolanle Balogun, a senior lecturer at the University of Lagos in Nigeria. “Even [say] I’m poor, and I’ll say I’m rich; I’m sick, I’ll say I’m not,” she said.

If people think the researchers are from the government, “they tend to put themselves lower on the scale, wishing something good will come out of it,” said Balogun, describing another scenario.

The scientists suggested that interviewers be trained to ask unbiased questions and gather unbiased responses when facing such challenges in the field by asking respondents questions in a third-person angle.

Another challenge that the conference highlighted is the potential for push back from  communities and repondents. “Conducting assessments interrupts [people’s] schedule for that particular day,” said Mbullo.

Respondents are sometimes bothered by the seemingly redundant assessments as researchers try to gather data that demonstrate patterns across time. After an unpleasant experience with surveys, some people refuse to answer questions and tell their community not to engage with researchers.

Balogun suggested that the research teams discuss the survey within a community prior to conducting fieldwork. Communicating with the local leaders and communities in advance can help people understand the purpose of the research and alllow for local buy-in.

Th HWISE consortium will continue refining the Household Water Insecurity Experiences scale to create a cross-cultural assessment for countries that are threatened by water scarcity.

See related story: Half the World Suffers from Water Shortages – Global Researchers Gather to Meet the Threat


Medill School Of Journalism, Media, Integrated Marketing Communications
1845 Sheridan Road, Evanston, IL 60208-2101 © 2020 Northwestern University