Climate change became front and centre in the White House race this week as both Donald Trump and Democratic nominee Joe Biden addressed the catastrophic wildfires raging in the American West. 

“We need to act on climate. Now,” Mr Biden tweeted on Monday following remarks in Wilmington, Delaware where he addressed the devastating blazes in California, Oregon and Washington, and hurricanes and tropical storms in the Gulf.

Mr Biden also called the president a "climate arsonist" condemning his reluctance to protect Americans “from the ravages of climate change”.

On Tuesday, the president called into morning show, Fox & Friends, to talk more about his environmental record.

“We have really good clean air, we have good clean water. Better than we had before,” Mr Trump said. 

Is this true?

 Not really.  While all six air pollutants measured by the Environmental Protection Agency (EPA) showed that the air was the cleanest on record in 2019, the most important pollutant, tiny particles, remained roughly the same as when Trump came into office, only down 1 per cent. 

Particle pollution, which comes from wildfires, wood-burning stoves, coal-fired power plants and diesel engines, can be deadly and is known to trigger asthma attacks, heart attacks, strokes and cause lung cancer.

The State of the Air 2020 report by the American Lung Association, which analysed data from 2016, 2017, and 2018, found that when it came to daily spikes in particle pollution, more cities experienced more days with increases and nine cities reached their most days ever reported. 

Some 24 of the 25 most polluted cities were located in the US west. 

The three years were also among the five hottest ever recorded. Changing climate patterns fuel wildfires and smoke which leads to deteriorating air quality from particle and ozone pollution. 

The Trump administration has rolled back or weakened more than two dozen policies related to air quality including  weakening emissions standards for vehicles set during the Obama administration, loosening regulations on release of mercury by oil and coal-fired power plants, and quashing a rule which required the oil and gas industry to report methane emissions.

According to Yale University’s global Environmental Performance Index 2020, the US is ranked 23rd in the world when it comes to safe drinking water, far behind other industrialised nations. 

According to the non-profit, Rural Community Assistance Corporation (RCAC), more than 30 million Americans lack access to safe drinking water. 

There have also been a number of rollbacks to legislation that protects US waterways including weakening of Obama-era pollution protections for wetlands under the Clean Water Act. The Trump administration also got rid of a proposal to reduce pollution from sewage plants and have put forward a plan to allow twice as long to remove lead pipes in water systems where lead levels are high.  

California, New York, Washington and 17 other states sued the Trump administration in July over rules that allow them to have the final say on federal projects, including pipelines and oil and gas facilities,  overriding state objections to threats to local water quality standards.

“We have less carbon now going up into the air than they had under the Obama administration," the president also told Fox.

Is this true?

Sort of - but Mr Trump has had little to do with it. In 2018, US carbon dioxide (CO2) emissions increased by 2.7 per cent after dropping for three years.  It was the second-largest spike since 2000, according to economic research group Rhodium.

The largest increase occurred in 2010 under President Obama as the economy jumpstarted following the 2008 recession, the report found.

In 2019, there was some good news when US CO2 emissions fell by 1.7 per cent –  but not enough to off-set the jump the previous year.

However Rhodium noted that net greenhouse gas emissions were still slightly higher in 2019 than when Trump became president.

The emissions fall was primarily driven by declining power generation from coal-fired plants - as the market turned away from the industry - despite Mr Trump’s battle to save it following his 2016 campaign promise.

John Nielsen-Gammon, a climatologist at Texas A&M University, told Politifact: “Overall there has indeed been an increase (or at best little or no change) in carbon emissions since Trump has been president.” 

The Trump administration has dismantled policies surrounding emissions including revising another Obama-era rule that would set limits on carbon emissions from new and refurbished power plants and set plans in motion to strike a rule by the previous administration that would require new coal-fired power plants to capture CO2 emissions. 

President Trump also made a number of claims on the wildfires and climate change during a briefing in California on Monday.

“When trees fall down after a short period of time, they become very dry — really like a matchstick. And they can explode. Also leaves. When you have dried leaves on the ground, it’s just fuel for the fires."

Is this true?

The overwhelming majority of climate scientists are in agreement that although fires are part of the ecosystem in some regions, climate change is making them more frequent and more intense as conditions become hotter and drier.

On Monday, California Governor Gavin Newsom acknowledged that his state had not done enough to manage forests and that more than a century of fire suppression has allowed fuel to build up.

But he reminded Mr Trump with a colour-coded, piechart handout that 57 per cent of forests in California are under federal management - and just 3 per cent are state lands. 

"It'll start getting cooler. You just watch,” the president shot back.

In a rare public rebuke of a sitting president, Mr Crowfoot replied: "I wish science agreed with you."

Mr Trump countered: "Well, I don't think science knows actually."

Is this true?

No. Although there are short-term fluctuations, the long-term trend is that global temperatures are rising, as data shows from both NASA and the federal National Oceanic and Atmospheric Administration.

And some 97 per cent or more of climate scientists agree: climate-warming trends over the past century are extremely likely due to human activities, NASA reports.