Whenever a gas is dissolved in a liquid, a small amount heat is liberated in the process. So dissolving a gas in liquid is overall an exothermic process.

So according to the LeChatelier principle, whenever the temperature is increased for a reaction which is exothermic in nature, the equilibrium shifts backwards and the reaction proceeds in backward direction that means the solution gets dissociated and will give off gas and hence solubility of gas decreases.

So with the increase in temperature, the solubility of the gases in liquids decreases.