I realize that there's almost no ancient written artifacts in South East Asia and when I see why the only reason I can think of is the harsh climate for any records. Then I realize that it's the same for all regions around the equator so I'm wondering if it's really because of that or just because there's no one writing it? Especially compared to any other regions especially the Mediterranean let alone the cradle of civilizations where written records can be found from even millenniums before.
This is a really interesting question! When looking at written sources there are a lot of variables that goes into longevity of the document. One of the reasons why we have a lot of epigraphic evidence from Mesopotamia, Egypt, and Greece, comes from the materials they were created from. All of those civilizations wrote their inscriptions on relatively durable materials (i.e. fired clay, rock) and these cultures practiced and maintained archives that has allowed historians a better look at these civilizations. For instance, in Mesopotamia many temples and palaces maintained relatively detailed archives of the daily and yearly runnings of these institutions. So these are examples of what historians *have* before the common era. But there are many reasons why we might not have epigraphic evidence from a lot of other cultures. Climate does affect this if cultures were creating inscriptions on unfired clay, or on degradable materials without significant archival practices. However, there could be a plethora of other reasons why we might not see any epigraphic evidence. Some of those could be the writing practices of the civilization and if they valued artistic representation in lieu of written, or even oral transmission of ideas. We simply cannot know exactly *why* certain cultures didn't produce written inscriptions the way other cultures did before the advent of their own written traditions, but climate definitely plays a part if the materials they were writing on weren't durable. However, that would be the only reason why climate might play a part, in my opinion. Other reasons could be that these regions were largely tribal throughout their histories, and tribal documents usually comes from artistic examples because they tend to be created on more durable materials. For South East Asia specifically, we would tend to see a lot of Jade artifacts being traded with more advanced civilizations such as Indian, Chinese, and Japanese kingdoms.
For my sources and further reading:
Mark W. Chavalas, ed. The Ancient Near East. Malden: Blackwell Publishing, Ltd., 2006.
Van De Mieroop, Marc. A History of the Ancient Near East ca. 3000 - 323 BC. Third Edition. John Wiley and Sons, Inc., 2016.
Waerzeggers, Caroline. “The Babylonian Priesthood In The Long Sixth Century BC.” Bulletin of the Institute of Classical Studies 54, no. 2 (2011): 59–70.
Gardner, Helen. "Gerdner's Art Through the Ages." ISBN-13 (cause I forget the rest) 978-0495573678.