The Basic Answer
No. Not for the standard United Nations and climate activist prescriptions generally given to us: speaking out and lobbying; transforming your transport, energy usage, diet, and dress; planting trees, buying local, and investing in alternative energy sources.
But, yes, if by fighting climate change we mean giving Zakat directly to people made eligible for Zakat because of the ecological disasters and losses climate change has inflicted upon them.
Understanding the processes and purposes of Zakat
Here’s the widespread misunderstanding Muslims have of Zakat. We equate Zakat generically with charity that can go to any cause we deem beneficial to people. This, in fact, is the function of sadaqah, in its now common sense of “voluntary charity.” (See How Many Types of Sadaqah Are There?)
We make this false assumption about Zakat because we have lost familiarity with Revelation (wahy) in its two forms: “Recited” (the Quran), and “Unrecited” (the statements, practices, and approvals of the Prophet, on him be peace). Zakat’s legitimate objects and sources come directly from these two authorities alone. Our mistake comes from replacing the ordainments of Allah and His Messenger, on him be peace, with our personal suppositions.
When you think about Zakat, remember this simple duality: Zakat comes due on wealth. Zakat is paid to people.
Put another way, we owe part of our yearly superfluous growable riches to people, not causes — even good ones.
More exactly, Zakat is a divinely obligated (1) percentage of alms-charity on (2) set types of wealth that (3) come into the possession of individual Muslims at (4) certain amounts within (5) specific time frames as the Prophet, on him be pace, designated each of these five factors; which is then collected and (6) paid out only to the eight kinds of people that Allah Himself delimited. (See What Is the Difference Between Sadaqah and Zakat?)
As to Zakat’s obligation of payment upon the wealth of Muslims and the limited eligibility of its recipients, Allah set it down for us in this verse:
Indeed, prescribed charitable offerings are only to be given to the poor and the indigent, and to those who work on administering it, and to those whose hearts are to be reconciled, and to free those in bondage, and to the debt-ridden, and for the cause of God, and to the wayfarer. This is an obligation from God. And God is all-knowing, all-wise” (Surat Al-Tawbah, 9:60) .
Allah uses the Arabic plural sadaqat (s. sadaqah), “charitable offerings,” to mean the obligatory Zakat, a common Quran usage of sadaqah. Its plurality indicates that this obligatory Zakat comes due on various wealth-streams, or types. You can count in the verse (ayah) the eight categories of people Allah declares Zakat-eligible, or Zakatable.
The Prophet Muhammad, on him be peace, the specifier of Zakat’s basic rules for Muslims, emphasized to us that we are not allowed to go beyond the eight classifications of people designated for Zakat by Allah in our distribution of it. The context is someone asking him for payment from the collected Zakat:
Allah does not leave the distribution of the sadaqah [meaning here Zakat] to a prophet, nor anyone else. He Himself prescribes the distribution to eight categories [of people]. If you are of one of the categories, I shall give you as you deserve” (Abu Dawud).
A big majority of Muslim scholars see these two Texts of (Recited and Unrecited) Revelation as exclusionary. No other people or needs are eligible for Zakat. Not even mosques, schools, or beneficial public works are Zakatable — including those fighting climate change. (See Can Zakat Be Paid for a Mosque?)
Isn’t fighting climate change part of fighting “in the path of God”?
No, according to the overwhelming scholarly majority. It means supporting those directly engaged in legitimate "physical struggle" in the path of God, the agreed upon meaning of this Arabic phrase, fi sabili’Llah, since the time of the Prophet, on him be peace. This remains the only consensus meaning of this category by all scholars, as well. (See this discussion in Can Zakat Be Given for Education?)
What of climate change’s effects on the Zakat eligibility of people?
There can be no doubt about the increasingly disastrous effects of climate change on the conditions of people and the earth — flooding, hurricanes, typhoons, and cyclones; heatwaves, fires, drought, and famine; and tens of millions of impoverished orphans, displaced, and climate refugees — effects that instantly place many such victims into some of these Zakatable categories.
But we should be cautious in the government and corporate media blizzard of an increasingly whitewashed presentation that climate change “in a black box” is the primary cause of such disasters. The fact is that it is the world’s already fast-growing poor and weak that such climate disasters devastate disproportionately. This is not a coincidence.
Why do these catastrophes tend to occur at the intersection of climate change and human vulnerability — in Africa, in South and East Asia, in Latin America, in the war-ravaged Middle East?
Why does the wealthy Global North — the nations spewing virtually all the earth-warming fossil fuel emissions into the air and responsible for the most material consumption and food waste in the world — suffer the smallest human effects of climate change catastrophe? Yet why do the vulnerable, discriminated-against populations in these lopsidedly wealthy nations suffer health and social stability effects on par with the poor and vulnerable in the hardest climate-hit peoples on earth?
The truth is most victims of the world’s increasing weather calamities are already Zakat eligible because of long-standing, glaringly unjust political, economic, and social imbalances perpetrated by an incorrigible war-and-wealth complex of politicians, merchant princes, and generals.
How can we help climate-change victims?
Sadaqah, voluntary charity, is not only the open way to helping people devastated by weather-related disaster. It is necessary for each one of us to give it, in any of its unlimited ways we can, if we are to minimally meet the unprecedented and growing, colossal humanitarian crises ravaging our world today.