Previous studies suggested a small number of big rivers accounted for most of ocean plastics.
But higher-resolution data suggests many more small rivers play a big role.
To cover 80% of plastic inputs you need to tackle > 1,000 rivers.
1/
Factors that matter a lot for a river's plastic inputs:
– waste management practices
– distance to coast
– cities nearby
– precipitation rates
– slope of terrain
Here are the top 10 rivers 👇
(most are small rivers in the Philippines)
2/
Previous modelling did not have such high-resolution data on topography, terrain, climate etc.
Therefore put more emphasis on the *size* of the river basin. So it assumed: large river basin = lots of plastic inputs.
That's why the latest results are markedly different
3/
The regional distribution of plastic inputs is similar to previous studies.
Most plastic inputs come from rivers in Asia (81%).
4/
But some of the smaller countries in Asia play a larger role.
One-third comes from the Phillippines. It has a lot of small rivers with cities close to the coast.
5/
What people often get wrong about plastic pollution:
They underestimate how important waste management is.
It's not the case that using more plastic use = more pollution.
Most rich countries contribute very little because they manage the waste.
6/
Improving waste management is not a sexy solution. Most people find it boring.
But if you're serious about tackling plastic pollution, this is where to put your focus and investment.
7/
"China uses more cement in 3 years than the US did in the entire 20th century".
I see this claim a lot & was curious if it stacked up against data on CO₂ emissions from cement.
So, some more back-of-the-envelope fact-checking below ↓↓
Spoiler: yes, seems to stack up
I'm using annual data on CO₂ from cement prod from @gcarbonproject & CDIAC. You can explore, compare countries, download from our CO₂ data explorer here: rb.gy/szuwvo
My calcs:
CO₂ from cement in USA for entire 20th century = 1838 million tonnes
Annual CO₂ from cement in China (2018) = 781 million tonnes
China emits same in 2.4 years as US in 20th century.
The study highlights a few key points:
– most of our soils have a 'lifespan' much greater than this.
– poor soil quality is still a problem in some areas
– we can increase this soil quality with proper management practices.
This is one of the key paragraphs 👇
Many have tried to find a credible source for the "only 60 years of harvest left" claim, and struggled to find one.