A dramatic factor within itself, not a dramatic quantity compared to everything else.
I'm not sure exactly how much aviation fuel China burned in 2025, nor mass to orbit, but a quick search suggests that in 2024 they burned 38.2 million tonnes of aviation fuel[0], and launched 174.4 tonnes to orbit[1]. For the sake of a Fermi approximation, round that up to 40 MT aviation emissions and 200 tonnes to orbit, and assume a 20x factor of propellant CO2 emission mass to payload mass:
200 * 20 = 4e3 tonnes of CO2 from space launches
40e6 / 4e3 = 10,000 times more comes from aviation
So, space could go up by a factor of 100x (compared to 2024) and still be a literal rounding error compared to just aviation.
As per article, graph shows the nation as a whole is just over 12,000 million tonnes "from fossil fuels and cement".
12e9 / 4e3 = 3,000,000
If I download the image to get the full resolution, there's 586 pixels between the lines for 10,000 million and 12,000 million tonnes, so each pixel on that graph represents 2e9 / 586 ~= 3.4 million tonnes, and 3.4e6 / 4e3 = 850, so even if space launch grew by a factor of a thousand it would only shift that graph by one pixel. One and a bit, but closer to one.
[0] Search for "38.2": https://www.greenairnews.com/?p=7427
[1] Page 13: https://planet4589.org/space/papers/space24.1.0.pdf
