West advises how to combine these ingredients into a personalised “formula”. You smoke because the nicotine you have been inhaling for all those years has changed your brain chemistry to create powerful urges to smoke.
The urges come about because every puff on a cigarette sends a rapid nicotine hit to the part of your brain that makes you do things, creating an association between the drug and the action.
With other positions West currently holds, including co-director of the NHS Centre for Smoking Cessation and a board member of QUIT, he is one of the leading experts in the field.
Pre-industrial (recent history) levels are said to have been at around 280 parts per million.
The other very disturbing issue is that the figures below don't include other greenhouse gases such as methane, which are also on the rise.
A child mummy is found high in the Andes and the archaeologist says the child lived more than 2,000 years ago.
How do scientists know how old an object or human remains are?
These urges are triggered because nicotine has trained the part of your brain that gets you to do things to light up a cigarette whenever you find yourself in a situation where you would normally smoke, be it with drinking alcohol, at a bus stop, after a meal.
Crucially, this helps to answer a conundrum that a lot of smokers have: why do smokers who don’t smoke every day often find it really hard to stop?
You probably have seen or read news stories about fascinating ancient artifacts.
At an archaeological dig, a piece of wooden tool is unearthed and the archaeologist finds it to be 5,000 years old.
This page is regularly updated with atmospheric carbon dioxide level data; based on the previous month in the current year and history of saturation levels for the same month dating back to 1958.
The readings are taken at the Mauna Loa Observatory, Hawaii.
The average saturation levels in the table below are in parts per million.