Learn Hardcore Japanese: kono mondai ha sinkoku desu kara, hayaku taisaku wo kentousimasyou. - This problem is serious, so let's consider countermeasures quickly.

深刻 (shinkoku) is a na-adjective (形容動詞). When a na-adjective comes at the end of a sentence in polite speech, you add です to make it grammatically correct and polite. So 深刻です simply means “is serious” in a polite register.

Why is ですから used instead of だから?

Both ですから and だから mean “so” or “therefore,” linking a reason to a result. The difference is formality:

だから is casual.
ですから is the polite/formal version, built on the copula です plus から.
Since the whole sentence is polite, ですから fits the register.

What role does は play in この問題は? Could I use が instead?

は is the topic marker, indicating “as for this problem….” It frames “この問題” as what you’re talking about. If you used が, you’d mark it as the subject emphasizing “the problem” itself, often to introduce or emphasize new information. In this case, we’re setting up a known topic (“this problem”), so は is correct.

What nuance does 早く add? How is it different from 早めに?

早く is the adverbial form of 早い, meaning “quickly” or “soon.” It stresses speed/urgency: “Let’s consider countermeasures quickly.”
早めに means “a bit earlier” or “in advance,” implying “sooner than planned,” but less urgent.

What does 対策 mean? Are there similar words I could use?

対策 (taisaku) means “countermeasure” or “course of action” to address a problem. Similar terms:

手段 (shudan): “means” or “method,” more general.
処置 (shochi): “measure” or “action,” often immediate or medical.
But 対策 specifically carries the nuance of planning measures against a threat or issue.

Can you explain 検討しましょう? What grammatical form is this?

検討しましょう is the polite volitional form of 検討する (to examine/consider). Volitional + ましょう gives a suggestion or invitation: “let’s consider.” It’s softer and more inclusive than a direct command.

How is 検討する different from 考える or 検査する?

検討する: implies a careful, methodical consideration, often in business or planning contexts.
考える: general “to think,” doesn’t imply thorough analysis.
検査する: “to inspect” or “to examine” in the sense of checking for defects or medical tests.

Why use から instead of ので for the reason clause here?

Both から and ので can mean “because.”

から is more direct, suitable for stating clear reasons before giving advice or commands.
ので is slightly softer, more explanatory or apologetic.
In a business or task-oriented context like this, から is common to clearly link the seriousness of the problem to the need for action.