A person must have a kind of discipline. First thing when you go to sea and see people that put rest of food in the beach which causes pollution. Second thing, we are talking about manufactors that places toxic element in the sea, we could conclude reason behind climate change.

Hmm, ok tbh this is a little unclear, although I think I can somewhat discern the likely intended meanings.
•"A person must have a kind of discipline."
-Is this regarding the thread title?
(ie:
"Do you believe that climate change is the biggest threat at the moment?")
-or instead regarding the questions presented by Shortie's OP?
(ie:
"What are your thoughts on climate change? Do you feel it is the biggest threat at the moment or is it scaremongering?")
-Nevertheless if meant as the premise for an argument:
"A person must have a kind of discipline." -this would be logically erroneous. However if instead the statement is meant as an opinion only, then it is of course perfectly reasonable.
•"First thing when you go to sea and see people that put rest of food in the beach which causes pollution."
-I'm inclined to think you probably mean *trash rather than *food? Simply because food generally gets eaten or otherwise rapidly decomposes. Whereas trash, eg: plastic food wrappers definitely is a significant aspect of the pollution problem and as such to this extent therefore I would agree, although I would disagree with this
"causing pollution" but rather being part of it as well as being an effect resulting from broader social issues.
•"Second thing, we are talking about manufactors that places toxic element in the sea, we could conclude reason behind climate change."
-Yeah I can definitely agree that certain corporate controlled manufacturers are dumping extraordinary quantities of highly toxic chemical waste byproducts straight into the worlds waterways & oceans and of course this inevitably leads to increasingly toxified ocean environments.
Although this is in no way the -
"reason behind climate change."—as the simple fact is that the Earth's climate has always been changing. Earth's climate never ceases changing. It would appear this glaring fact has been ignored by the "climate change" fearmongers due to the obvious—that their fallacious narrative requires that all blame, all responsibility & all punishments must be assumed by you, and by me, and by everyone—except the privileged hypocrite class such as saint Greta and saint Gates....

whom demand you, me & everyone, but certainly not themselves, must forfeit the use of industrial products—meanwhile the likes of saint Greta & saint Gates freely fly around in private aircraft pumping out magnitudes more pollution than the vast majority of the rest of us.

There's an interview by Anderson Cooper -with Bill Gates gleefully stating:
"I probably have one of the highest greenhouse gas footprints of anyone on the planet. My personal flying alone is gigantic."