Tens of billions of dollars have been spent globally on climate and climate change research. Much has been learned about what the climate has been in the past and what the current climate is in the multiple climate regions on the globe. Our knowledge is far more precise for the period during which the climate has been monitored by measurement instruments, compared with our knowledge of prior periods documented only by proxies. Our knowledge has become far more comprehensive in the satellite era because the percentage of the globe measured has increased.
We know that the globe has been, on average, far cooler and far warmer than it is today. We do not know what caused those major swings in temperature. More fundamentally, we do not know what the optimal average near-surface temperature in each individual regional climate or the optimal global average near-surface temperature is for the occupants of each climate region and the processes occurring in each region. Therefore, we do not know whether the recent global average temperature increase is moving toward or away from the optimum.
We know that the portion of the globe covered by ice has been greater than and less than the current ice coverage percentage. We know that glaciers have been retreating globally, though we do not know whether that retreat is on the path to optimal glacial coverage.
We know that sea level has been far lower than it is today and that it has been increasing relatively steadily for hundreds of years. Again, we do not know whether sea level is changing toward or away from an optimal level. Similarly, we know ocean temperatures are increasing and ocean water is becoming slightly less alkaline, but we do not know whether these are changes toward or away from an optimum.
We know that anthropogenic activity has increased the concentrations of Carbon Dioxide, Methane and Nitrogen Dioxide in the atmosphere. We know that the increased Carbon Dioxide concentration has contributed to the warming of the globe. We also know that the increased Carbon Dioxide content has contributed to global greening and to the increased production of food crops. We also know that the combination of increased Carbon Dioxide and increased Nitrogen Dioxide concentrations have led to more efficient use of available water by a variety of plant types. We do not know the optimal concentrations of these atmospheric gases to promote global greening and enhanced plant growth.
The most profound thing we don’t know is the extent to which the climate will continue to change due to a combination of natural variability and anthropogenic influences. Recent research suggests that the future changes will be modest and beneficial. However, the champions of climate change control continue to assert that the climate is rapidly approaching multiple potential “tipping points” and that the globe could rapidly become uninhabitable. They claim that extreme weather events are becoming more frequent and more dangerous and are causing increasing loss of life and property. However, the available data do not support those assertions.
Originally published here.