Replacing corroded metal a major
environmental issue, study finds
Newswise — COLUMBUS, Ohio
– Every year, the United States spends nearly a trillion dollars fighting
metallic corrosion, an electrochemical reaction that occurs when metals oxidize
and begin to rust. By taking on this surprisingly insidious issue, researchers
have now estimated how much corrosion is gradually worsening global carbon
emissions.
Global steel production
has been rising steadily for decades – and because steel has poor resistance to
corrosion, part of that demand is to replace steel used in construction
materials that have become corroded over time, in everything from bridges to
automobiles. Reducing the amount of steel that needs to be replaced due to
corrosion could have measurable effects on how much greenhouse gases are
produced to make steel, said Gerald
Frankel, co-author of the study and a professor in materials science and engineering at The Ohio State University,
Though previous studies
have estimated the current economic cost of corrosion to be about 3 to 4% of a
nation’s gross domestic product, this new study, led by Ohio State alum Mariano
Iannuzzi, is the first to quantify the environmental impact associated with
steel corrosion.
The study was recently
published in the journal npj Materials Degradation.
“Given society’s reliance
on coal fuel, iron and steel production is one of the largest greenhouse gases
emitters of any industry,” said Frankel. “But most of the costs associated with
the industry actually stem from the energy that goes into creating steel, and
that energy is lost as the steel reverts to rust, which is similar to its original
form of iron ore.”
The time it takes steel to
corrode largely depends on the severity of the environment and the alloy
composition, but this environmentally expensive issue is only getting worse,
said Frankel.
Using historical carbon
dioxide intensity data to estimate carbon dioxide levels per year beginning
from 1960, the researchers found that in 2021, steel production accounted for
27% of the carbon emissions of the global manufacturing sector, and about 10.5%
of the total global carbon emissions worldwide. Corroded steel replacement
accounted for about 1.6 to 3.4% of emissions.
But there is some good
news, the study noted. Due to regulations placed on the steel industry,
technological advances in the steelmaking process have resulted in a 61% reduction
in energy consumption over the last 50 years.
Despite this improvement,
the results of the study are a call to action for policymakers and industry
officials to amend and coordinate international policy regarding steel
production and corrosion management, Frankel said.
“Coordinated international
strategies, as well as decreasing global steel demand, by using best practices
for corrosion mitigation, could better improve global corrosion management
strategies and drastically reduce the rise in greenhouse gas emissions we’re
seeing due to repeatedly replacing corroded steel,” he said.
If actions to improve
steel’s carbon footprint aren’t taken soon, the study notes that greenhouse gas
emissions produced by the steel industry could reach about 27.5% of the world’s
total carbon emissions by 2030, with corroded steel representing about 4 to 9%
of that number. Such a result would make the goals set by the Paris Agreement to limit Earth’s warming
to 1.5 degrees Celsius as well as the U.S.’s own domestic climate goals almost
completely unfeasible. The study notes that management strategies such as
taking advantage of machine learning technologies could be one of the best
chances we have to reduce Earth’s carbon dioxide levels.
That said, if humans
cannot meet these conditions, the consequences for Earth’s climate will be
dire, so more people need to be made aware that a low-carbon steel industry is
needed to prevent such a dystopia, said Frankel.
“Global warming is a
societal challenge that takes coordination of a lot of multidisciplinary
approaches,” said Frankel. “Our work is bringing to light an issue that seems
to have gone under the radar in terms of the importance of adding to the
problem.”