We usually do conferences in cryptography/security, and most of them have page limits: CCS, USENIX, NDSS, S&P, CRYPTO, EUROCRYPT all have page limits (some allow appendices, which reviewers are not obligated to read).
Yes, if you count the emissions for the stuff manufactured in China for (not only) european customers.
If you look at consumption-based emissions[0], China is at 7 t per capita, which is 8 t less than the US, 2 t less than Germany and about par with Denmark, Slovakia, and England.
There is no known polynomial time algorithm for TSP. AFAIK there are quantum algorithms for TSP with quadratic speedup in comparison to the brute force method (still exponential though).
The one thing quantum computers are (currently and theoretically) able to solve efficiently is the factorization problem, but are very much limited by low qubit number, i.e. engineering problems.