A new report has found that US carbon dioxide emissions rose by 3.4% in 2018 after three years of decline.
The spike is the largest in eight years, according to Rhodium Group, an independent economic research firm.
The data shows the US is unlikely to meet its pledge to reduce emissions by 2025 under the Paris climate agreement.
Under President Donald Trump, the US is set to leave the Paris accord in 2020 while his administration has ended many existing environmental protections.
While the Rhodium report notes these figures – pulled from US Energy Information Administration data and other sources – are estimates, The Global Carbon Project, another research group, also reported a similar increase in US emissions for 2018.
The US is the world’s second largest emitter of greenhouse gases.
And last year’s spike comes despite a decline in coal-fired power plants; a record number were retired last year, according to the report.
The researchers note that 2019 will probably not repeat such an increase, but the findings underscore the country’s challenges in reducing greenhouse gas output.
In the 2015 climate accord, then President Barack Obama committed to reducing US emissions to at least 26% under 2005 levels by 2025.
Now, that means the US will need to drop “energy-related carbon missions by 2.6% on average over the next seven years” – and possibly even faster – to meet that goal.
“That’s more than twice the pace the US achieved between 2005 and 2017 and significantly faster than any seven-year average in US history,” the report states.
“It is certainly feasible, but will likely require a fairly significant change in policy in the very near future and/or extremely favourable market and technological conditions. ”
What’s behind the rise?
Analysis by Matt McGrath, Environment correspondent, BBC News
There are a number of factors behind the rise in US emissions in 2018, some natural, mostly economic.
Prolonged cold spells in a number of regions drove up demand for energy in the winter, while a hot summer in many parts led to more air conditioning, again pushing up electricity use.
However economic activity is the key reason for the overall rise in CO2 emissions. Industries are moving more goods by trucks powered by diesel, while consumers are travelling more by air.
In the US this led to a 3% increase in diesel and jet fuel use last year, a similar rate of growth to that seen in the EU in the same period.
All this presents something of a problem for the Trump administration which has been happy to point to declining US emissions as a reason to roll back many of the environmental protection regulations put in place by his predecessor.
The figures also show that the President’s efforts to boost demand for coal have not succeeded yet, with electricity generated from this fossil fuel continuing to decline.
Despite this, there is little to cheer in the US data for those concerned with climate change on a global scale.
Many had hoped that carbon cutting actions at state or city level could in some way keep the US on track to meet its commitments made under the Paris climate agreement.
The latest emissions data indicate that this is unlikely to happen.
What has changed in the US?
The last time the US saw such an increase in emissions was in 2010, as the country recovered from its longest recession in decades.
Part of last year’s spike is also the result of economic growth, but new policies have exacerbated the effects of increased industry production.
Mr Trump has rolled back a number of his predecessor’s environmental regulations since taking office, appointing climate change sceptics and industry leaders to head US environmental agencies.
As a part of undoing what he called a “war on coal”, in 2017, Mr Trump rescinded the Clean Power Plan, which required states to slash carbon emissions to meet US commitments under the Paris accord.
In December, the Environmental Protection Agency (EPA) pressed ahead with plans to lift restrictions for carbon emissions from new coal plants and asked for public comment on redefining the phrase “causes or contributes significantly to” air pollution.
Under Mr Trump’s administration, the federal government has also opened up once-protected lands for oil and gas drilling across the US and has proposed ending regulations on fuel standards for cars and trucks after 2021.
“The big takeaway for me is that we haven’t yet successfully decoupled US emissions growth from economic growth,” Rhodium climate and energy analyst Trevor Houser told the New York Times.
The US jump also marks a worldwide trend: 2018 saw an all-time high for global CO2 emissions and was the fourth warmest year on record.
Source: BBC – https://www.bbc.co.uk/news/world-us-canada-46801108
Met Office researchers expect to record one of the biggest rises in atmospheric concentrations of CO2 in 2019.
Every year, the Earth’s natural carbon sinks such as forests soak up large amounts of CO2 produced by human activities.
But in years when the tropical Pacific region is warmer like this year, trees and plants grow less and absorb smaller amounts of the gas.
As a result, scientists say 2019 will see a much bigger CO2 rise than 2018.
Since 1958, the research observatory at Mauna Loa in Hawaii, has been continuously monitoring and collecting data on the chemical composition of the atmosphere.
In the years since they first started recording, the observatory has seen a 30% increase in the concentration of CO2 in the atmosphere caused by emissions of fossil fuels and deforestation.
Scientists argue that the increase would have been even larger without the ability of the forests, land and seas to soak up around half of the gas emitted by human activities.
This ability however, varies with the seasons.
In the summer, CO2 levels in the atmosphere fall as the trees and plants soak up more of the carbon as they grow. In the winter, when they drop their leaves, they soak up less and atmospheric levels rise.
But when temperatures are warmer and drier than normal, trees and plants grow less and absorb less. This natural variation is compounded in years when there’s an El Niño event, which sees an upwelling of heat from the Pacific into the atmosphere.
“The warm sea surface conditions now will continue over the next few months and that will lead into the vegetation response,” said Dr Chris Jones from the Met Office.
“Around the world this heat has different impacts. In some places, it’s hotter and drier and you get more forest fires. In a tropical rainforest, for instance, you reduce the natural growth of the vegetation.”
According to the Met Office, these limits on the ability to absorb CO2 will see a rise in concentrations this year of 2.75 parts per million, which is higher than the 2018 level.
They are forecasting that average CO2 concentrations in 2019 will be 411ppm. Carbon dioxide concentration exceeded 400ppm for the first time in 2013.
This year’s predicted rise won’t be as big as in the El Niño years of 2015-16 and 1997-98. However, there have only been increases similar to this year’s about half a dozen times since records began.
Researchers say the long-term trend is only going in one direction.
“The year-on-year increase of CO2 is getting steadily bigger as it has done throughout the whole of the 20th Century,” said Dr Jones.
“What we are seeing for next year will be one of the biggest on record and it will certainly lead to the highest concentration of CO2.”
Other researchers say the Met Office findings are worrying.
“The increases in CO2 are a function of our continued reliance on fossil fuels,” said Dr Anna Jones, from the British Antarctic Survey (BAS).
“Some tempering in the rate of increase arises from the Earth’s ability to absorb CO2 from the atmosphere, but that can change year-on-year as the Met Office forecast shows.
“What’s critical, however, is that the persistent rise in atmospheric CO2 is entirely at odds with the ambition to limit global warming to 1.5C. We need to see a reduction in the rate of CO2 emissions, not an increase.”
The Met Office scientists say that it doesn’t always follow that a record CO2 concentration will lead to a record global temperature in 2019, as there are many natural factors that can impact the final figure.
The researchers there are pleased that observations over the past four years show that their model is accurate. They believe it can be used in the future to help countries accurately attribute increases in emissions to their actions or to natural factors.
Source – BBC : https://www.bbc.co.uk/news/science-environment-46989789