经济与社会科学2025science.org
塑料袋禁令与收费减少了海岸线上的有害袋类垃圾
Plastic bag bans and fees reduce harmful bag litter on shorelines
入门 · 约 45 分钟读完前置知识：基础统计学、环境政策常识
导读
这篇论文研究塑料袋禁令和收费是否减少海岸线上的塑料袋垃圾，结论是这类政策能减少有害的袋类垃圾。评论主要争论研究按“件数”而非塑料重量统计，可能掩盖更厚的“可重复使用”袋以及替代垃圾袋带来的塑料总量反弹。
HN 关注点：环保政策是否真正有效，以及统计口径（件数 vs 塑料重量）会不会让政策效果被高估。
HN 评论精选
这几条评论里：质疑 1 亲历 1
质疑批评研究按件数而非重量统计，认为加州厚“可重复使用”袋和替代垃圾袋可能让塑料总量和微塑料不降反升。
研究发现，海滩垃圾中塑料袋所占比例在所有地区都上升了，所以这很糟。更令人担忧的是被丢弃袋子的性质：加州禁止了“一次性”塑料袋（过去我们会把它当浴室垃圾桶袋等重复使用），但允许在收银台花几美分买“可重复使用”袋；后者重得多，含塑料量多 10–100 倍，降解也更慢。该研究统计的是“件数”而非重量，并报告减少 25–47%。假设加州是达到 47% 的地区（就算 50%），而可重复使用袋只比禁令前糟 10 倍，那也意味着海滩上的微塑料增加 5 倍。我认为这是灾难，不是胜利。这与更早的研究一致：那些研究测量了加州式塑料袋禁令前后垃圾填埋场垃圾的总塑料含量，也显示塑料垃圾急剧增加。那些研究所在的地方不允许加州强制商店改用这种可重复使用塑料袋；作者发现人们从把一次性袋当垃圾袋，转为使用厨房垃圾袋，而后者糟糕约 100 倍。如果只有 1% 家庭用一次性购物袋装垃圾，且没人重复使用新式袋子，政策最终只是打平；实践中，这些政策增加了总塑料垃圾。
hedora查看英文原文
The study finds that plastic bags as a fraction of the waste on beaches increased in all areas, so that’s bad. A more concerning issue is the nature of the bags being thrown away. California banned “single use” plastic bags (which we used to reuse as trash bags for the bathroom or whatever) but lets you buy “reusable” ones for a few cents at the checkout counter. The reusable ones are much heavier and contain 10-100x more plastic, and take even longer to biodegrade. The study counts “items”, not weight, and reports a 25-47% decrease. Assuming California is the region that hit 47% (call it 50%), and the reusable bags are better than the best available (only 10x worse than pre-ban) that translates to a 5x increase in microplastics on the beach. I’d consider this a disaster, not a win. This matches older studies, which measured total plastic content of landfill waste before and after plastic bag bans like California’s. Those showed sharp increases in plastic waste too. The studies in question were in places that did not allow the reusable plastic ones that California forced the stores to switch to. Instead, the authors found that people switched from using the disposable bags as trash bags to using kitchen trash bags, which are ~100x worse. If only 1% of households were using disposable shopping bags for trash, and no one reused the new style bags, then the policies ended up breaking even. In practice, the policies increased total plastic waste, despite being better thought out than California’s newer ban. I’m all for banning plastic bags, but the current bans target the most efficient use of plastic, increasing overall plastic production and waste. The bans should only target things that have plastic-free alternatives, or at least that have less plastic intensive alternatives.
亲历海滩居民认为游客乱丢垃圾才是主因，禁令反而让垃圾和尿布更散落、更难处理。
作为住在海滩上、且在这些禁令之前就住在海滩上的人，塑料袋似乎从来不是大问题；真正的问题是大多数来海滩的人觉得把垃圾留在海滩上没什么。禁令前人们倾向于把垃圾好好装进塑料袋里，现在大家就随便丢，因为他们不想把垃圾放进用来装食品杂货的可重复使用袋里，那也意味着他们得处理垃圾，而不是“忘记”那袋塑料垃圾。最糟的是湿透的尿布大量增加，没人有一次性袋子装尿布，于是就直接留在海滩上。冲上海滩的垃圾袋和塑料袋，与海滩游客留下的垃圾相比微不足道；不住海滩的人不知道那有多少垃圾，因为我们这些住海滩的人为了海滩干净、准备再被弄脏，早晨散步和游泳时都在捡垃圾。
ofalkaed查看英文原文
As someone who lives on the beach and lived on the beach since before these bans, plastic bags never seemed much of an issue and the real issue is that most people who visit the beach think nothing of leaving their garbage on the beach. Before the ban people tended to leave their garbage nicely contained in a plastic bag, now everyone just leaves it strewn about because they don't want to put garbage in their reusable bags that they use for their groceries which also would mean they would have to deal with the garbage instead of "forgetting" their plastic bag of garbage. The worst is the massive increase in sodden diapers, no one has a disposable bag for the diapers so they just leave them on the beach. The garbage bags and plastic bag that wash up on the beach are insignificant compared to the garbage beach goers leave on the beach and people who don't live on the beach don't realize how much garbage that is because those of us who do live on the beach spoil our morning stroll and swim with picking up the garbage so the beach can be clean and ready to be spoiled all over again.
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