There have recently been some big news on the topic of climate change and the question of whether or not mankind is responsible for some of the changes that are being measured in our environment and the atmosphere.

First, the American Geophysical Union (AGU) recently released a new position statement on climate change:

Human activities are changing Earth’s climate. At the global level, atmospheric concentrations of carbon dioxide and other heat-trapping greenhouse gases have increased sharply since the Industrial Revolution. Fossil fuel burning dominates this increase. Human-caused increases in greenhouse gases are responsible for most of the observed global average surface warming of roughly 0.8°C (1.5°F) over the past 140 years. Because natural processes cannot quickly remove some of these gases (notably carbon dioxide) from the atmosphere, our past, present, and future emissions will influence the climate system for millennia.

Naturally, there are those who dissent from the official AGU position statement, among them Roger A. Pielke Sr., who states:

[We] were tasked to report on the most important aspects of climate change. This was incompletely done in the statement, where it inaccurately, in my view, presents a view of climate change that is dominated by the emission of carbon dioxide and a few other greenhouse gases.

His alternative position statement can be read here.

The New York Times is also reporting on an early draft from the Intergovernmental Panel on Climate Change that comments on climate change and our role in it:

An international panel of scientists has found with near certainty that human activity is the cause of most of the temperature increases of recent decades, and warns that sea levels could conceivably rise by more than three feet by the end of the century if emissions continue at a runaway pace.

These are complex and important issues that should not be taken lightly. And these are strong positions from two large organizations, the AGU and the IPCC. But the question remains, how serious is this and what needs to be done?