去年全球温室气体排放为何反弹?

• 全球温室气体排放在2021年有所增加，在2020年全球温室气体排放大幅下降后积聚的热情和希望受到了一定程度的打击  

• 现实情况是，主要的生活方式和工业变化是由疫情引起的，当世界再次开放时，温室气体排放量总是会增加  

• 然而，2021年的温室气体排放量仍比2019年下降5%，这可能表明全球温室气体排放轨迹发生了细微变化  

据美国油价网报道，尽管各国承诺削减碳排放并向可再生能源过渡，但全球温室气体排放量仍在上升。 对2020年全球排放量下降的乐观情绪(主要是由于对疫情防控的社交限制和生活方式的改变)以及对第26届联合国气候变化大会(COP26)提出的国际行动的热情，可能是被误导。

虽然世界各地的许多政府和能源公司都有碳减排和净零排放的雄心，但在低碳能源变得更广泛之前，我们可以期待看到高水平的碳排放。 与2020年相比，美国2021年的温室气体排放量增加了6.2%，尽管人们希望疫情期间的行为转变会推动持久的改变。 在疫情的第一年，环境活动人士强调，随着人们开始在家工作，不再频繁旅行，以及工业运营放缓，排放量有所下降。 有可能做出有意义的改变的想法，促使活动人士、年轻人，甚至政府提出改变的必要性。 

然而，在2021年，我们似乎在迅速倒退，世界上很多人又回到了老习惯。 由于道路和空中交通的恢复以及大多数行业的运营恢复，温室气体排放量必然会增加。 例如，与2020年相比，2021年美国的交通行业的温室气体排放增加了约10%。 

进行这项研究的荣鼎集团(Rhodium Group)的凯特•拉森表示：“我们预计会出现反弹，但令人沮丧的是，温室气体排放反弹的速度甚至快于整体经济。”事实上，“我们不仅在减少经济中的碳强度，我们还在增加它。”“我们现在做的恰恰是我们应该做的事情的反面，”拉森解释道。  

显然减排任务还有很长的路要走，在去年严重的石油和天然气短缺之后，世界上有好几个国家转向了煤炭——最脏的化石燃料——来弥补这一缺口。 尽管近几年来美国的煤炭使用量下降，但2021年的煤炭发电产量比2020年增加了17%。 这不仅发生在美国。 根据国际能源署(IEA)的数据，煤炭产量在2021年创下历史新高，需求水平将在2022年达到峰值。 

英国目前计划在2024年之前逐步淘汰所有的煤炭生产，而且似乎走上了正确的轨道，在去年夏季实现了具有里程碑意义的三天无煤期，但英国不得不在去年9月运行燃煤发电厂以满足国内电力需求。 由于面临天然气短缺和价格大幅上涨，英国又转而使用煤炭为国内供电。

拉森说，“与我们在2020年至2021年期间看到的一些变化相比，全球温室气体排放量被认为上升了4.9%，在过去一年里，大约有360亿吨二氧化碳被排放到大气中。 在欧洲，去年春天欧盟国家的温室气体排放量增加了18%。 家庭贡献了近五分之一的温室气体排放，主要的罪魁祸首是交通行业和供暖。

全球碳项目主席罗布·杰克逊谈到这一趋势时说：“我们预计，当世界经济恢复到接近正常水平时，就会出现温室气体排放反弹。” 拉森补充道：“把汽车停开一年，当你再开的时候，它还是一辆污染严重的汽车。 同样道理，当经济活动恢复时，温室气体排放也会恢复。”

杰克逊说，“然而，我们有理由抱有希望，因为2021年的温室气体排放量比2019年下降了5%，这表明变化可能正在发生，只是没有以许多人希望的速度发生。 在1990年至2020年期间，尽管欧盟人口增长，旅游人数增加，温室气体排放量却下降了31%。 这反映了政府鼓励减排政策的转变，以及过去30年对可再生能源投资的增加。 当政府和能源公司共同努力实现改变时，它表明有改变的潜力。”

世界上许多政府都在依靠油气公司来降低排放，提高该行业的税收，并要求石油巨头扩大投资组合，将低碳石油生产和可再生能源项目纳入其中。 但是，要实现有意义的改变，政府、公共机构和私营部门必须共同努力，以COP26承诺的速度发展可再生能源领域。 许多国家的目标是到2050年前实现净零排放，如果他们希望实现这一目标，他们将不得不加快能源转型的步伐。  

李峻 编译自 美国油价网

原文如下：

Why Global Emissions Bounced Back In 2021?

·     Global greenhouse gas emissions increased in 2021, denting some of the enthusiasm and hope that had built up after a significant drop off in 2020

·     The reality is that major lifestyle and industry changes were caused by a global pandemic and emissions were always going to increase when the world opened up again

·     The emissions in 2021 were still down five percent from 2019 however, which might point to a slight change in the trajectory of global emissions 

Greenhouse gas emissions are up worldwide despite big promises for carbon-cutting and a transition to renewables. Optimism around the drop in emissions throughout 2020, mainly owing to pandemic restrictions and a change in lifestyle, as well as enthusiasm around international action coming out of COP26, was perhaps misguided. 

While many governments and energy companies around the world have carbon-reduction and net-zero ambitions, we can expect to see high levels of carbon emissions until low-carbon energy becomes more widely available. Emissions in the U.S. rose 6.2 percent in 2021 compared to 2020 despite hopes that a shift in behavior during the pandemic would spur lasting change. Throughout the first year of the pandemic, environmental activists highlighted the drop in emissions that occurred as people began to work from home, stopped traveling so much, and as industrial operations slowed down. The idea that it was possible to make a meaningful change led activists, youths, and even governments to suggest the need for change. 

Yet, in 2021 we seem to have backtracked rapidly, with much of the world population returning to old habits. As road and air traffic picked up and operations resumed across most industries, emissions were bound to increase. For example, there was around a10 percent increase in transport emissions in the U.S. in 2021 compared to 2020.

Kate Larsen, from the Rhodium Group that carried out the study, stated “We expected a rebound but it’s dismaying that emissions came back even faster than the overall economy.” In fact, “We aren’t just reducing the carbon intensity of the economy, we are increasing it. We are doing exactly the opposite of what we need to be doing,” she explained.

There is clearly still a long way to go and following severe oil and gas shortages last year, several countries around the world turned to coal – the dirtiest fossil fuel – to bridge that gap. Despite the use of coal in the U.S. declining in recent years, coal energy production increased by 17 percent in 2021 from 2020. And this was not only the case in America. Coal production was set to hit an all-time high in 2021 according to the International Energy Agency (IEA), with demand levels peaking in 2022. 

The U.K., which currently plans to phase out all coal production by 2024 and seemed to be on the right track - achieving a landmark coal-free three-day period in the summer - had to run coal plants in September to meet electricity demand. As the country faced natural gas shortages and a significant hike in prices, it shifted back to using coal to power the nation.

In relation to several of the changes we saw between 2020 and 2021, worldwide greenhouse gas emissions are thought to have risen by 4.9 percent, with approximately 36 billion tonnes of carbon dioxide being released into the atmosphere over the past year. In Europe, greenhouse gas emissions from EU countries increased by 18 percent last spring. Households contributed just under a fifth of emissions and the main culprits were transportation and heating. 

Rob Jackson, chair of the Global Carbon Project stated of the trend, “We expected this rebound when the world’s economy returned close to normal.”, adding “Park your car for a year and it’s the same polluting vehicle when you start it again. Similarly, when economic activity returns, so do emissions,” he explained.

There is reason to be hopeful, however, as 2021 greenhouse gas emissions were down by 5 percent from 2019, suggesting that change may be taking place, just not at the speed many had hoped for. Across the EU, greenhouse gas emissions dropped by 31 percent between 1990 and 2020, despite a growth in population and an increase in travel. This reflects the shift in government policies to encourage emissions cuts as well as the increased investment in renewable alternatives over the last three decades. It demonstrates the potential for a shift when governments and energy companies work together towards change. 

Many governments around the world are relying on oil and gas companies to lower their emissions, increasing taxes on the sector and requiring oil majors to expand their portfolios to include low-carbon oil production and renewable energy projects. But to make meaningful change, governments, public institutions, and private players must work together to develop the renewable energy sector at the rate promised coming out of the COP26 summit. With many countries aiming for net-zero by 2050, they will have to pick up the pace of the energy transition if they hope to achieve this goal.