Unintended consequence

The release of helium balloons and chinese lanterns is fast being recognised as a menace. The balloons are made of latex rubber and normally have strings attached. The bulk of them when they’re released rise to 7,000m to 8,000m and then burst due to changes in atmospheric pressure. The latex and string then become heavier than air and fall back to earth or, in the case of many balloons released, into the sea. Some of the balloons are described as being biodegradable or eco-friendly. Even these remain a threat for some time. The latex takes about 12 months to degrade in salt water and about half that on land. Synthetic fibre strings take even longer.
They pose three kinds of threat to wildlife. The first is ingestion. They are eaten by creatures like whales and dolphins, marine turtles and, in some cases, cattle. The marine creatures may mistake the latex for jellyfish, it’s hard to know what the cattle were thinking.
As for Chinese lanterns,  the same problems are posed as well as the risk of starting fires when they land or confusing coastguards who may mistake them for distress flares.