More than 500 million people live in the Middle East and North Africa, which has always been hot in summer. And it's getting hotter, says Jos Lelieveld, Director at the Max Planck Institute for Chemistry and Professor at the Cyprus Institute. The number of extremely hot days has doubled since 1970, he says, and "the very existence of its inhabitants is in jeopardy." 

In computer models, European scholars estimate substantially different climate change impacts for global warming of 1.5°C and 2°C by 2100, the two temperature limits policy makers agreed on in the Paris climate agreement.

The simulation concluded that an additional 0.5°C would mean a 10-cm-higher global sea-level rise by 2100, longer heat waves, and would result in virtually all tropical coral reefs being at risk. 

When we published a paper in 2013 finding 97% scientific consensus on human-caused global warming, what surprised me was how surprised everyone was.

Ours wasn’t the first study to find such a scientific consensus. Nor was it the second. Nor were we the last.

The signatory countries of the Kyoto Protocol and the newer Paris Agreement have committed to reduce global warming, but they can only use estimates and projections to verify whether they are actually achieving the necessary reduction in greenhouse gases.

The uncertainties are considerable and mistakes do happen.

Researchers funded by the Swiss National Science Foundation (SNSF) have developed a method to independently monitor these statistics by making direct measurements of the gases in the atmosphere.

Hardly any natural gas pipeline leaks

Planes flying between Europe and North America will be spending more time in the air due to the effects of climate change, a new study has shown.

By accelerating the jet stream -- a high-altitude wind blowing from west to east across the Atlantic -- climate change will speed up eastbound flights but slow down westbound flights, the study found. The findings could have implications for airlines, passengers, and airports.

This is a flight time infographic (c) University of Reading. Credit: University of Reading

Now that natural gas has signaled the end of the biggest source of greenhouse gas emissions, coal power plants, researchers are turning to other ways to optimize so that efforts to make energy too expensive for poor people won't come into effect.

One such effort is to add alum to chicken litter, which reduces ammonia and greenhouse gas concentrations and emissions, specifically carbon dioxide, in poultry houses. 

Acid-based chemical compounds, alum and PLT - another amendment - that are added to the bedding material in poultry houses prior to the birds entering have proven to be a very effective tool in controlling ammonia emissions.

Methane is increasing in the atmosphere, though poor understanding of the sources has led to rampant speculation by environmental groups.

By compiling previously reported measurements made at a total of 733 northern water bodies - from small ponds formed by beavers to large lakes formed by permafrost thaw or ice-sheets - researchers are able to more accurately estimate emissions over large scales. 

A study sheds new light on how the tilt of the Earth affects the world's heaviest rainbelt and ths the climate overall. Data from the past 282,000 years shows a connection between the Earth's tilt, called obliquity, that shifts every 41,000 years, and that the movement of a low pressure band of clouds that is the Earth's largest source of heat and moisture -- the Intertropical Convergence Zone.

The climate is complex and nothing shows that more than when numerical models are forced to stop predicting the past and have to actually project what could happen in the future.

But the past can at least inform if models are really wrong and an analysis of fossil corals and mollusk shells from the Pacific Ocean reveals there is no link between the strength of seasonal differences and El Niño, a complex but irregular climate pattern with large impacts on weather - but the top nine climate models in use today simplistically associate exceptionally hot summers and cold winters with weak El Niños, and vice versa.

Not much is predictable about climate, despite assurances by politicians and activists meeting in Paris, and one claim that global warming skeptics use - that more CO2 is good for plants - is also correct but also not predictable.

Instead, inter-annual variation in climate has stronger effects on predators such as spiders than populations of their detritivorous prey, such as isopods, which could lead to changes in food chain length, which can in turn influence decomposition and plant growth. These findings emphasize the importance of combined approaches that consider food webs and physiological processes to understand the consequences of global climate change.