Ilmastomuutos lisää sekä hellettä että tulvia monissa maissa.

Lisää here is the 3rd person singular present tense of the verb lisätä (“to increase, to add”).

• Ilmastomuutos = subject (“climate change”)
• lisää = “increases / adds”
• sekä hellettä että tulvia = objects (“both heatwaves and floods”)

So structurally it is: [subject] + [verb] + [objects] + [adverbial].

Note: lisää can also be a noun/adverb meaning “more” in other contexts, but here it clearly functions as a verb because it is followed by object nouns in the partitive case.

Helle (“hot weather, heatwave conditions”) is mostly treated like a mass/uncountable noun in this type of sentence. Finnish uses the partitive case for:

1. Indefinite quantities (“some, more of” something)
2. Ongoing, non-completed, or non-delimited events/effects
3. Many mass nouns as objects

Lisätä very often takes a partitive object when it means “to increase/add some amount of X” rather than “to complete X as a whole”.

• Ilmastomuutos lisää hellettä.
  → Climate change increases some amount of heat / hot weather (not a single, countable “unit of heat”).

If you used bare nominative helle here, it would sound ungrammatical in standard Finnish in this structure. The partitive hellettä fits the idea of “more/extra hot weather” rather than a specific, bounded “whole” object.

The base noun is tulva (“flood”).

Key forms:

• Nominative singular: tulva
• Partitive singular: tulvaa
• Nominative plural: tulvat
• Partitive plural: tulvia

In the sentence we see tulvia = partitive plural. This suggests many floods / flooding events in general, not just one indefinite flood.

Rough nuances:

• Ilmastomuutos lisää tulvia.
  → increases floods/flooding (plural, in general, repeatedly)

• Ilmastomuutos lisää tulvaa.
  → increases the amount of flooding (more like one continuous phenomenon; less idiomatic in this exact sentence, though understandable)

• Ilmastomuutos lisää tulvat.
  → wrong here, because with lisätä in this sense, the object expressing “more X” is not a total object; tulvat (nominative plural) would be used as a subject or in other structures, not as this kind of object of lisätä.

So tulvia matches the idea “more floods (plural, various instances of flooding)” and stays parallel to hellettä in expressing an indefinite amount.

Yes. The structure is:

• lisää = verb
• sekä hellettä että tulvia = two coordinated objects of that one verb

Because sekä … että coordinates the two nouns as a single unit, they must:

• share the same syntactic role (both are objects of lisää), and
• be in the same case (here, partitive: hellettä, tulvia).

You cannot mix cases here, e.g. sekä hellettä että tulvat would be wrong in this construction. Both need to match what lisää requires: an indefinite, “more of X” type partitive object.

Sekä … että is a correlative pair meaning “both … and …”.

In this sentence:

• sekä hellettä että tulvia ≈ “both heatwaves and floods”

Difference from ja:

• ja = “and”, neutral, very common:
  • lisää hellettä ja tulvia = “increases heatwaves and floods”
• sekä … että:
  • somewhat more emphatic and a bit more formal/written
  • explicitly highlights that both elements are included

You could say:

• Ilmastomuutos lisää hellettä ja tulvia.
• Ilmastomuutos lisää sekä hellettä että tulvia.

Both are correct; the second just stresses the “both … and …” relationship a bit more.

Monissa maissa means “in many countries”.

It is in the inessive plural, which typically answers “where?” and often translates to “in, inside” in English.

Breakdown:

• moni (“many”) → monissa (inessive plural)
• maa (“country, land”) → maissa (inessive plural)

Together:

• monissa maissa = “in many countries”

So both the quantifier moni and the noun maa are in inessive plural, agreeing with each other.

In Finnish, adjectives and quantifier-like words usually agree in case and number with the noun they modify.

Here:

• Noun: maa → maissa (inessive plural)
• Quantifier: moni → monissa (inessive plural)

They match in:

• number (plural)
• case (inessive, “in”)

So monissa maissa is the regular, correct pattern.

A form like moni maissa or monissa maa would be ungrammatical. In noun phrases, you generally inflect all the relevant words, not just the final noun.

Yes. Finnish word order is fairly flexible, and different orders mainly change the emphasis.

Original:

• Ilmastomuutos lisää sekä hellettä että tulvia monissa maissa.
  → neutral; starts with the subject (“climate change”), ends with the place (“in many countries”).

Alternative:

• Monissa maissa ilmastomuutos lisää sekä hellettä että tulvia.
  → puts more emphasis on monissa maissa (“in many countries” is the starting point or contrastive topic).

Both are grammatically correct. The basic rule is that the finite verb usually comes early (often second), but objects and adverbials (like places, times) can be rearranged for focus and style.

Both are used in real Finnish for “climate change”.

• ilmasto = “climate”
• muutos = “change”
• ilmaston = genitive (“of the climate”)

Forms:

• ilmastonmuutos literally “change of the climate”
• ilmastomuutos literally “climate change” as a compound without the genitive link

In practice:

• Ilmastonmuutos is more common and is usually considered the “standard” form in written Finnish.
• Ilmastomuutos also occurs and is understood the same way; some speakers just prefer one or the other.

In your sentence, Ilmastomuutos is perfectly understandable and natural, though in many textbooks and news texts you’ll more often see Ilmastonmuutos.

Finnish has no articles like English a/an or the.

Definiteness and specificity are shown by:

• context
• word order
• sometimes pronouns or other structures

So Ilmastomuutos can mean:

• “climate change” in general (here, that’s the natural reading)
• or “a climate change” in some very specific context, if that made sense

Similarly, hellettä and tulvia don’t have explicit “some / the” markers. The partitive plural and the general context tell you this is about some amount of heatwaves and floods in general, not one specific, well-defined set.

Yes, you could say:

• Helle ja tulvat lisääntyvät monissa maissa.

This uses the intransitive verb lisääntyä (“to increase, to become more numerous/frequent”) instead of the transitive lisätä (“to increase/add [something]”).

Differences:

• Original: Ilmastomuutos lisää sekä hellettä että tulvia monissa maissa.

  • climate change is the agent/doer that increases something
  • lisätä
    • partitive objects (hellettä, tulvia)

• Alternative: Helle ja tulvat lisääntyvät monissa maissa.

  • helle and tulvat are now the subjects
  • they themselves “increase” or “become more common”
  • lisääntyä is intransitive, no object

Meaning-wise they’re very close. The original explicitly attributes the increase to ilmastomuutos, while the alternative just states that heat and floods are increasing, with the cause implied or left to context.