"The first Obama Administration’s climate policy was largely indistinguishable from George W. Bush’s and it fought having to regulate greenhouse gases almost as hard as its predecessor. Only after the 2012 election did it show any appetite for actual emissions regulation, and by then it was mostly too little, too late. As I previously noted, the low priority Obama gave to climate issues makes his policy legacy fragile. While his second administration took some steps to reduce emissions, only about half of it will matter – and, as discussed below, even that may be outweighed by their mistakes."
"President Trump’s unfortunate and misguided rollback of environmental protections has led to a depressing and widespread belief that the United States can no longer meet its commitment under the Paris climate change agreement. But here’s the good news: It’s wrong.
No matter what roadblocks the White House and Congress throw up, the United States can — and I’m confident, will — meet the commitment it made in Paris in 2015 to reduce greenhouse gas emissions that are warming the planet. Let me explain why, and why correcting the false perception is so important."
"President Trump will sign sweeping executive orders Tuesday that take aim at a number of his predecessor's climate policies.
The wide-ranging orders and accompanying memorandums will seek to undo the centerpiece of former President Obama's environmental legacy and national efforts to address climate change.
It could also jeopardize America's current role in international efforts to confront climate change.
A senior White House official says the goal is to make the U.S. energy-independent and to get the Environmental Protection Agency back to its core mission of maintaining clean air and water."
"The CO2 measured at the Mauna Loa Baseline Atmospheric Observatory in Hawaii hit 405.1 parts per million last year, the National Oceanic and Atmospheric Administration announced. That’s an increase of 3 parts per million, which matched the record of 3 parts per million in 2015. It marks five consecutive years of CO2 increases of at least 2 parts per million, an unprecedented rate of growth, said Pieter Tans, lead scientist at NOAA’s Global Greenhouse Gas Reference Network."
“The rate of CO2 growth over the last decade is 100 to 200 times faster than what the Earth experienced during the transition from the last ice age,” Tans said. “This is a real shock to the atmosphere.”
"The number is significant because the amount of carbon dioxide in the atmosphere was 280 parts per million from about 10,000 years ago until the start of the Industrial Revolution. The monthly global average nosed above 400 parts per million for the first time in March 2015 and is now increasing at a faster pace, according to NOAA researchers. What’s more, carbon emissions stay in the atmosphere for years, so even as some emissions have been reduced in recent years, the global average level continues to climb. In 1960, they were about 300 parts per million, suggesting a precipitous climb in a relatively short period of time since then."
"Last year marked a milestone, with levels passing the 400 ppm mark permanently. This year scientists expect carbon dioxide to briefly reach 410 ppm this spring before the seasonal cycle of northern plant growth brings it back down a bit, continuing the ever-rising seesaw."
"The rapid rise of carbon dioxide and other greenhouse gases in the atmosphere has caused the planet to warm roughly 1.8°F since the start of the Industrial Revolution. The world has had back-to-back-to-back hottest years on record since 2014. The corresponding heat has also caused glaciers to melt, seas to rise and altered atmospheric circulation patterns around the globe."
Sea ice in the Arctic has been melting at a record-breaking pace. Scientists blame a warming climate for most of that, but researchers have now teased out a natural cycle for how Arctic sea ice melts year-to-year.
Based on that cycle, they conclude that 30 percent to 50 percent of the melting is due to natural causes, while human-caused warming is responsible for the rest.