Atmospheric

Cosmic rays from supernovae can influence Earth´s cloud cover and how that influences climate could be useful for making better models.

A new study shows how atmospheric ions, produced by the energetic cosmic rays raining down through the atmosphere,help the growth and formation of cloud condensation nuclei – the seeds necessary for forming clouds in the atmosphere. When the ionization in the atmosphere changes, the number of cloud condensation nuclei changes affecting the properties of clouds.

More cloud condensation nuclei mean more clouds and a colder climate, and vice-versa.
The realization that livestock like cows are ruminants - and produce a lot of methane while chewing - was a real boon to vegetarian activists because they got to say curbing meat would mean less global warming.

Methane has 23X the warming power of the more popular CO2 in climate change estimates but it drastically shorter in duration. Still, that is enough. When natural gas caused American CO2 emissions from energy to plummet back to early 1990s levels, solar and wind lobbyists and their environmental allies claimed that methane, which they had endorses as an alternative to coal for decades, was suddenly a crisis.
Tablet and phone marketing executives can sleep well tonight. While those devices are commonly blamed for recent sleep problems, beams of pure digital energy shot straight into the eyeballs will do that, a new paper seeks to shore up the failing claim that tiny particulate matter, PM 2.5 (2.5 microns per cubic meter of air), is impacting human health and should be the source of new regulations by the Environmental Protection Agency.
Though the trend has been to listen to environmental claims about the benefits of trees in cities, in science they have a well-established dark side: in urban cities, they produce a lot of ground-level ozone, the very thing environmentalists spent decades lobbying against.

During hot days, trees emit compounds that worsen ozone, such as formaldehyde, which forms from isoprene, a volatile organic compound that trees can give off when temperatures are hot, and 
terpenes, which also interact with sunlight to create a "natural" smog. If you have witnessed the haze of the Great Smoky Mountains, you are breathing in natural pollution.

The court case over whether ExxonMobil may have deliberately downplayed the potential dangers of global warming is heating up. Eleven attorney generals have filed a brief in US District Court in Manhattan supporting a lawsuit by Exxon to halt a probe by their peers in New York and Massachusetts.

Though subways reduce overall pollution emissions in cities, what is good for society may not be good for the poor people who ride mass transportation. A new study finds that Canadian subways personal exposure to certain pollutants, and that Toronto has the highest levels in Canada.

Sounds awful for city dwellers, right? Breathe easy, the pollutant they measured has yet to be linked to any harm, and no acute deaths, outside government claims when they want to restrict businesses. 
Everyone knows the value of trees in the cycle of atmospheric life. They consumer carbon dioxide (CO2), the target of regulations for the last few decades.

But that's not the only way they keep us cool. Trees also impact climate by regulating the exchange of water and energy between the Earth's surface and the atmosphere, which should be important considerations as policymakers contemplate efforts to conserve forested land.
We think we know the perfect balance of gases in the atmosphere, and it involves a time before there was any industry, when the human population was tiny, when almost all of the planet was covered in plants. Basically, the dream of environmental groups today (with their members being the few allowed to live, of course.)

But we don't really know. There have been times when the carbon dioxide in the atmosphere was 10X what it is today, but we were only slightly warmed, and there were times when it was lower than today, and we were covered in ice. What we do know is that things are pretty good now, and we don't want a planet covered in ice, or to live in a greenhouse. 
Dear Mr. Trump, Please Can We Study Our Climate?

To the President-elect,

Sir,

    please consider that if climate scientists of the past had not been supported by wealthy patrons we of the 21st century would know little if anything about how to warn people that a hurricane, storm surge or tornado is imminent.

Atmospheric scientists at the Desert Research Institute (DRI) have turned their attention toward the growing e-cigarette industry and found that toxic aldehydes, such as formaldehyde, are formed during the chemical breakdown of the flavored e-liquid during the rapid heating process (pyrolysis) that occurs inside e-cigarettes or electronic nicotine delivery systems (ENDS).

Since the dose makes the poison, is this a concern? Not really, but in the modern world of International Agency for Research on Cancer (IARC) hazard assessments, risk has become irrelevant and the presence of any compound, even in trace levels, is declared carcinogenic if the levels are within seven orders of magnitude, so 10,000,000 to 1.