Scientists: time is running out before the effects of climate change are "irreversible"

Global temperatures could reach an irreversible tipping point within 12 years if the world does not act dramatically to reduce the amount of carbon dioxide released into the atmosphere, scientists warned in a new report.

This assessment highlights President Donald Trump and the Republican-controlled Congress. Trump and many of his most ardent supporters in Congress have questioned climate change attributable to men and the president could remain in office nearly half the time, according to scientists, essential for action.

The UN panel on climate change said the impact of climate change could be further slowed if countries around the world take unprecedented steps to reduce their use of fossil fuels and release less carbon dioxide and other greenhouse gases in the air.

But the US government has not supported aggressive climate policies under the Trump administration.

President Trump has decided to withdraw the United States from the Paris Climate Agreement – an agreement under which countries pledged to significantly reduce greenhouse gas emissions. The current administration has decided to cancel most climate policies proposed by the Obama administration, proposing in some cases replacements that, according to experts, would not go so far. in reducing emissions.

The Environmental Protection Agency declined to comment on the findings of the UN report on Monday.

"The United States continues to lead the world in reducing greenhouse gas emissions by reducing their emissions by 14% since 2005," said a spokesman for the EPA in a statement.

Researchers from the UN group found that "human-made" carbon dioxide emissions were to be reduced by almost half of the 2010 levels by 2030 in order to avoid the worst effects of climate change. Scientists have stated that "rapid, far-reaching and unprecedented changes in all aspects of society" are needed to limit the risk of irreversible environmental damage.

The Trump administration has taken steps to protect producers of coal and other sources of energy, such as natural gas, by saying that relying solely on renewable energy poses a risk to national security.

However, many scientists believe that one of the most effective ways to combat global warming would be to significantly reduce the use of fossil fuels in the country.

According to researchers, global temperatures have already risen by an average of 1 degree Celsius, about 1.8 degrees Fahrenheit, above pre-industrial levels. A warmer half degree might not seem important for an average person.

But even this amount of change should destroy the coral reefs, threaten to melt the Antarctic ice sheets, which could contribute to rising sea levels that aggravate floods, make the ocean more acidic and impact crops in some parts of the world.

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Michael Mann, professor of atmospheric science at Penn State University, explains that the goals to stop warming to 1.5 or 2 degrees Celsius are often considered a cliff, but that reality looks more like a minefield. Climate models can not accurately predict when irreversible impacts of climate change could be triggered, but we should stop going in that direction as soon as possible.

"We do not know where these critical points are, we do not know how much warming triggers these effects, so it's another reason to stop this progress," he said.

According to Mann, the first thing the United States and other countries need to do is to define the amounts of carbon dioxide emitted by burning fossil fuels and accelerate the switch to more renewable energy.

He said that we already felt the impact of rising temperatures, as warmer oceans and sea level rise were contributing to worsening storms, such as hurricanes, but if we continue to release more carbon dioxide and other greenhouse gases that warm the atmosphere, storms like the one we experienced this summer will only get worse.

"The strongest storms are getting stronger because of the warming of the oceans and they will continue to do so," he said.

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John Holdren, professor of environmental policy at the Harvard Kennedy School of Government and former scientific adviser to President Barack Obama, said there was no way to limit warming to 1.5 ° C without a aggressive aggression on the part of every country.

"This report is very striking in its assertion that climate change is an urgent and potentially irreversible threat to the planet," he said.

Holdren said it was very difficult to take action to reduce emissions without the federal government, but the good news is that states, cities, universities and private companies have made considerable efforts to achieve the goals. Paris Accord goals even without the leadership of the administration. This coalition, nicknamed "We are always present", even took part in the events of the United Nations separately from the official American delegation.

"I'm not optimistic about our ability to keep the increase at 1.5%." I think doing what the IPCC report described as necessary to reach 1.5% would be almost miraculous in the world of Today, starting with the fact that the US government is now the only country in the world is not attached to Paris.It is an extremely heavy carrier to get to 1.5 ", said Holdren.

But Holdren said that despite the specific purpose of this report, the effects of climate change will only worsen if temperatures continue to rise, so it's important to take steps to prevent that the consequences do not worsen.

He added that even though it was unlikely that most countries would achieve the goals set by the UN Panel of Experts, the glass is both half empty and half full, because emissions have decreased overall.

Mann said he was cautiously optimistic about trends in reducing carbon dioxide emissions, but that it needed policies to accelerate this trend and combat the warming that has already occurred, what neither the current government nor the Republican leadership in Congress sees.

"The most important thing that Americans can do in the next month is to vote in the next election and vote on this climate issue."

ABC News & # 39; Karma Allen contributed to this report.