5 ms·

Why not around 50'000 years ago when sapiens drove most megafauna of Australia into extinction?

Retric 9y ago
In 20 million years it's going to be hard to get something dated to within 100,000 years. So, the fact the die-offs started slightly before this layer of radioactive elements is probably not going to be noticeable. Similarly the dinosaurs did not die of exactly 65,000,000 years ago it was 65,170,000 plus or minus ~640,000 years. On top of that humans have probably killed of more species after 1965 than before 1965.
- lkrubner 9y ago
  This is exactly why choosing a specific year, such as 1965, is political. It would be intellectually honest if they posted a range, with a large error margin.
  - tritium 9y ago
    Well, consider that one way or another, we've written ourselves into the geological record, as much as we've written our own history about ourselves. History, often airbrushed, is a sociological exercise, and so, it's always been a soft science. Geological and cosmological history is filled with hypothesized events and broad revisions in the face of emergent (if subtle) proof against common views and norms. Lots of hypothetical place holders aren't apolitical at all. The big bang is pretty political, despite the background radiation that serves as "reasonable evidence" that something like the big bang might have occurred. The truth being that we don't honestly know why a universe would be created through a big-bang-like process, even though it's the best interpretation of the evidence we have access to, lately. Large error margins are artifacts of incomplete information, and that doesn't mean incomplete information is truly preferable. We have pretty good information about 20th century events, even if the particulars of the social landscape are hotly debated.
    - lkrubner 9y ago
      "We have pretty good information about 20th century events" We don't have specific dates for when the vast majority of extinctions have happened. We have a rough idea of what the base line extinction rate was for the last million years, and we have good data suggesting that the trend has been up for maybe 10-20,000 years, give or take several thousand years. Picking a specific year, such 9,874 BC, or 434 AD, or 1965 AD, is arbitrary, and a political act.
      - tritium 9y ago
        Is presence of species and biological diversity more relevant than transient geological evidence, asteroid impacts and tectonic activity? Without geological evidence (fossils) we would have no benchmark for non-living species. Arguably, all geological timescales and frames of reference (as named by humans, and thus innately political) are based, not on biological taxonomy and known degrees of species diversity, but rather, on geological records, for which radioactive markers from weapons testing carried out by humans, remains a relevant and valid point of reference that may outlast us.
      - Retric 9y ago
        Not really, they are simply using the date related to a specific event which has error bars measured in months and expecting people to relate that event to the extinction. If WWIII happens and we have a full scale nuclear exchange then that's likely to be used as the peak. Really, it's not a political statement just an interesting observation.
refurb 9y ago
Impossible. We all know that ancient people lived in harmony with nature.

In 20 million years it's going to be hard to get something dated to within 100,000 years. So, the fact the die-offs started slightly before this layer of radioactive elements is probably not going to be noticeable. Similarly the dinosaurs did not die of exactly 65,000,000 years ago it was 65,170,000 plus or minus ~640,000 years. On top of that humans have probably killed of more species after 1965 than before 1965.

lkrubner 9y ago
This is exactly why choosing a specific year, such as 1965, is political. It would be intellectually honest if they posted a range, with a large error margin.
- tritium 9y ago
  Well, consider that one way or another, we've written ourselves into the geological record, as much as we've written our own history about ourselves. History, often airbrushed, is a sociological exercise, and so, it's always been a soft science. Geological and cosmological history is filled with hypothesized events and broad revisions in the face of emergent (if subtle) proof against common views and norms. Lots of hypothetical place holders aren't apolitical at all. The big bang is pretty political, despite the background radiation that serves as "reasonable evidence" that something like the big bang might have occurred. The truth being that we don't honestly know why a universe would be created through a big-bang-like process, even though it's the best interpretation of the evidence we have access to, lately. Large error margins are artifacts of incomplete information, and that doesn't mean incomplete information is truly preferable. We have pretty good information about 20th century events, even if the particulars of the social landscape are hotly debated.
  - lkrubner 9y ago
    "We have pretty good information about 20th century events" We don't have specific dates for when the vast majority of extinctions have happened. We have a rough idea of what the base line extinction rate was for the last million years, and we have good data suggesting that the trend has been up for maybe 10-20,000 years, give or take several thousand years. Picking a specific year, such 9,874 BC, or 434 AD, or 1965 AD, is arbitrary, and a political act.
    - tritium 9y ago
      Is presence of species and biological diversity more relevant than transient geological evidence, asteroid impacts and tectonic activity? Without geological evidence (fossils) we would have no benchmark for non-living species. Arguably, all geological timescales and frames of reference (as named by humans, and thus innately political) are based, not on biological taxonomy and known degrees of species diversity, but rather, on geological records, for which radioactive markers from weapons testing carried out by humans, remains a relevant and valid point of reference that may outlast us.
    - Retric 9y ago
      Not really, they are simply using the date related to a specific event which has error bars measured in months and expecting people to relate that event to the extinction. If WWIII happens and we have a full scale nuclear exchange then that's likely to be used as the peak. Really, it's not a political statement just an interesting observation.

refurb 9y ago

Impossible. We all know that ancient people lived in harmony with nature.