There are other factors that could be contributing to the recent warming of the Earth, solar irradiance being one of them. Changes in solar radiation could have a possible impact on the warming of the Earth, since it is Earth's main energy source. However, scientists do not agree that it is natural causes alone that are causing rising temperatures.
Though it may be natural causes, there is a high probability that human activities do have some influence on the changing climate. The emission of Carbon Dioxide is no means good for the environment, whether or not it is the sole source of an increasingly warmer Earth. Regardless of the cause of global climate change is completely human based - which is highly unlikely - we all must remain extra careful of what we allow to be emitted into the atmosphere that protects us all.