人類健康：治療成因，不是症狀

在室內用這些燃料烹飪時產生的煙霧和煙塵可能導致心臟和肺部疾病，以及癌症和中風。 由於這些疾病，{每年有43萬人因室內空氣污染而提早死亡 ，大部分在發展中國家，如下圖所示。

These traditional cooking methods also contribute 2-5% of global yearly greenhouse gas emissions , both through burning the fuels themselves and from the activities required to gather them .

But it’s not only the amount of emissions produced from traditional cooking practices that cause problems. The types of pollution produced are problematic for both the climate and our health too . Open fires and inefficient stoves often have poor air-circulation around them, leading to the production of “black carbon” (a major component of soot) .

So, how much of a problem is black carbon for the environment?

Even though there is less black carbon in the atmosphere than CO₂, it is currently the second biggest contributor to global warming because it absorbs so much heat . However, unlike CO₂, black carbon is quickly removed from the atmosphere by rain . While CO₂ continues to cause warming for hundreds of years after it has been emitted, the contribution of black carbon to global warming would end quickly if we stopped producing it .

This makes solutions that reduce black carbon emissions particularly promising: if all black carbon emissions stopped, the effects would be seen within only a matter of decades !

Improved cookstoves (either solar-powered or fuel-burning) can cut emissions by as much as 95%  as well as saving lives. By reducing black carbon and other pollutants, it is estimated that 150 million clean cookstoves could help avoid 2.2 million early deaths in India .

There are even more benefits! Improved cookstoves use less fuel, which reduces the time people spend gathering firewood. This is a physically demanding and often dangerous task, especially for unaccompanied women .

運輸造成的室外空氣污染

阻止室內空氣污染只是故事的一半。 交通運輸是{室外 空氣污染的主要來源，佔2014年全球溫室氣體排放量的16％。 據估計，2015年交通運輸的排放導致385,000例早期死亡。

Swapping to electric cars is one possible solution, as they produce less pollution on the road . However, they don’t solve other problems caused by cars, such as traffic accidents. They also only reduce emissions if renewable energy is used to produce the electricity.

By contrast, taking public transport (such as buses, trams and trains) reduces pollution per passenger as well as traffic. This is especially the case if the vehicles are full of passengers and are run on clean fuels or electricity .

Even better are active forms of transport, such as walking and cycling. These have the biggest positive impact on both health and solving climate change .

Walking and cycling reduce emissions, improve local air quality, and help prevent diseases related to inactive lifestyles .

Governments can encourage people to walk and cycle more through cost-effective strategies, such as improving pavements and cycleways .

我們為什麼要將健康與氣候變化聯繫起來？

The World Health Organisation estimates that air pollution causes as many as one in eight deaths , as well as contributing to climate change.

Politicians tend to avoid strong climate change policies due to their perceived costs , and because the climate benefits to their country are only felt if many other countries do the same .

On the other hand, the health benefits of reducing air pollution from cars and cookstoves are felt quickly and by the people in that country .

Therefore, thinking about the immediate health benefits of reducing air pollution may help persuade politicians to take action on emissions. These policies aim to improve public health, but they also tackle climate change. Win-win!

實現2016年《巴黎協定》在氣候變化上的目標，到2050年，每年將因空氣污染而挽救一百萬以上的生命。 而且，這些政策將在改善健康帶來的收益遠超過支出，例如提高健康工人的生產力和減少醫療衛生支出。

保護自然有益於我們的健康

Thinking about both the climate and human health could also persuade politicians to reduce deforestation.

Cutting down trees not only results in carbon emissions , but can also lead to more disease outbreaks. How? 75% of new infectious diseases in humans come from animals . These are called “zoonoses” .

當森林被砍伐，並在其中修建道路時，人類更容易接觸到生活在那裡的動物。這意味著疾病更有可能在人類和動物之間傳播 。

In the recent past, human impacts on the natural world have been linked to a number of viral epidemics and pandemics . These include COVID-19 (2019-ongoing), Zika (2015-19) and SARS (2002-04) . Outbreaks of Ebola and Malaria have also been linked to deforestation .

Preventing the loss of forests could reduce the chance of future disease outbreaks  at the same time as limiting carbon emissions .

And that’s not the only health reason for conserving nature. A growing body of evidence suggests that experiencing nature can have great benefits for our physical and mental wellbeing . Put simply, being around plants and animals makes us happy !

In one study, it was found that patients who could see green areas from their hospital windows recovered from their surgery faster and used fewer painkillers than similar patients that had no such views !

飲食和健康

我們的飲食不僅影響我們的健康，而且影響地球的健康。

目前，我們生產的糧食足以滿足全球人口的需求，但這種分配方式不平均。 全球11％的人口營養不良，這意味著他們沒有足夠的食物來維持正常健康的生活。 同時，2017年全球肥胖造成的死亡人數佔8％。

Eating too much meat (particularly red and processed meats ), processed food, and sugary drinks increases the likelihood of obesity, as well as type 2 diabetes and some cancers .

This diet is also extremely bad for the environment ! Far more emissions are released when meat is produced than plant-based foods because energy is lost higher up the food chain . What’s more, animals like cows and sheep are the greatest contributors to global emissions of methane, a greenhouse gas that is even more powerful than CO₂ . The environmental impacts of eating meat are covered in more detail in the Food and Farming course.

There are internationally agreed guidelines on healthy eating . These recommendations only consider the health outcomes of diets, and advise eating more plant-based food and less meat and sugar . This diet is much better for the environment !

If people followed these existing guidelines, greenhouse gas emissions from our diet would decrease by 29% .

The latest research suggests that these guidelines should now be updated to recommend even less processed food and meat . To find out more about food and the environment, check out our ’Food and Farming’ course!

結論

更健康的飲食，炊具清潔和運輸方式選擇只是我們可以同時改善全球健康和減緩氣候變化的三種方式。 充分理解並利用這些聯繫可能會激發政客對氣候危機採取迅速有效的行動。

 回饋意見

https://climatescience.org/zh-tw/advanced-human-health/

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