Considering the urgency and massiveness of the current eco-crisis, the lack of political action or its non-proportionality is astounding and worth discussion. A common stereotype is that politicians are striving after political power, are corrupted by other powerful lobbies of the rich and are lying to the people, who are per definition in a democracy defined as the ultimate sovereign and the force of good. However, I think that these things are more delicate and I would rather argue that people get the government they deserve.
Let’s imagine as example that two politicians are competing in an election and it turns out that the construction of a new airport becomes a critical issue. Politician Mr Pink says that he will build the airport for 5 billion euros to state-of-the-art standards, but will have to increase taxes by 5%. However, his competitor Mr Brown says that Mr Pink has no clue whatsoever and actually he can build the airport for 3 billion euros also to state-of-the-art standards and will invest the remaining 2 billion euros in social housing. As a voter it is often hard to tell who is right, but if he is not sure he should rather vote for the candidate who is offering the better package, shouldn’t he? Once in power, it is easy for a politician to explain why for this and that reason, e.g. changes in the global market, the costs will increase by 10% (and will increase them step-by-step multiple times). Voters are usually very forgiving, and often just interested to feel good about themselves, their politicians, and the rest of the world. Even when politician Mr. Pink is completely competent and honest and finally right, he is very likely to loose the election.
I guess, this scenario sounds very familiar to many of us, and because this “wishful thinking” of voters is present, it is clear why politicians in power are lying, because politicians not lying, will never (ok, let’s say rarely) be elected. In addition, in my opinion the majority of the voters is primarily motivated by their immediate, individual interest, and not by the greater good for society. Hanna Arendt [¹] and climate scientist Hans-Joachim Schellnhuber  have also described this sort of secret memorandum of understanding between voters and votees, which serves both their egotistical, short-term interests, but may damage the long-term interest of the overall society (see also functional stupidity).
In relation to the climate crisis, it seems that politicians are not telling the brutal truth about the actual crisis and necessary changes in society, but play down the actual situation or focus on other topics, since they are afraid of loosing political power if they make their electorial uncomfortable. Voters on the other hand gratefully listen to their politicians to avoid the anxiety and pain of required actions, and continue their convenient lifestyle they are used to in a state of denial.
 Hanna Arendt (1972). Wahrheit und Politik. In: Wahrheit und Lüge in der Politik. Zwei Essays. München: Piper.
Original in English: Hannah Arendt (1976-02-25). TRUTH AND POLITICS. The New Yorker.
 Richard David Precht (2018). Ist die Erde noch zu retten? URL: https://www.youtube.com/watch?v=FBEHnrriMkM