While enganged in our regular routine we are always so busy and concerned about future planning but did we ever thought that there are lots of behind the scene progress is going on which we never thought of and which not only destroy out future but also the entire mankind. Yes we are talking about some serious concerns and they are as follows :  

Nuclear warfare

Nuclear war is the use of nuclear weapon like atomic bomb ,hydrogen bomb on enemy country . the most dangerous type of war if started.The military conflict or political strategy between two country in which nuclear weapon used to inflict damage on the enemy.
The nuclear, radiological, chemical, biological or other weapon if used can kill and harm a large number of humans or cause great damage to human-made structures (e.g., buildings), natural structures (e.g., mountains), or the biosphere.
This can bring about the extinction of the human race. A lot of smoke and dust , heat will be produced .
The Ozone Layer Will Be destroyed, the ozone would result from heat absorption in the upper stratosphere, which modify wind and ozone-destroying nitrogen oxide will be drawn in.
Nuclear famine mass starvation occurs due to disrupted agricultural production and distribution.
low temperatures, killing frosts, UV radiation from the sky, few crops will survive long Electromagnetic pulse Nuclear winter
An Electromagnetic Pulse -pulse sent out by detonating a single atomic bomb was so powerful that it blew out street lamps, TV sets. Smoke Will Block Out The Sun
Temperature drop-Cold To Grow Food- Sun blocked from the sky, the world’s temperature will drop.

 Volcanic eruption

Supervolcano eruptions are a part of Earth’s history.Largest volcanic eruption on Earth is Ibe the Mount Toba eruption in Sumatra. When a volcanic eruption is erupted then lava covered everything in sight , ash rained down hard enough to choke everything. Super volcanic eruptions are caused by earthquakes underneath the Earth's crust causing magma to escape. 

Due to Super volcanic temperature drop lead to winter as ash blocking the sunlight for up to six to eight years, cooling down the earth - lasting 1000 year that result to cause mass extinctions of humans, animals and plants.

Supervolcano eruptions lists:-
 KATLA (Iceland)last erupted: 1918
 CUMBRE VIEJA (La Palma, Canary Islands)Last erupted: 1971
MT. VESUVIUS (Italy) Last erupted: 1944
POPOCATÉPETL (Mexico) Last erupted: 2000
YELLOWSTONE "SUPERVOLCANO" (U.S.) Last erupted: 640,000 years

When volcano erupts, the entire chamber will empty out onto the surface in an explosive decompression event.This is threat to our modern civilization,unstoppable and ferociously destructive.
 Sulfurous volcanic gases produce acid rains.
Chlorine-bearing compounds present threat to ozone layer.
 Release carbon dioxide that lead to greenhouse-effect warming.

 Asteroid

 Asteroid is a large, irregularly shaped object in space which enter the earth atmosphere and some time reach earth surface, impacts on a planet's surface topography, global climate and life.
Geological significance impact-related mass extinction explosions so massive powerful that they vaporized all the Earth's oceans
 major extinctions, like extinction of the age of dinosaurs. probably caused by the airburst of an asteroid
 asteroid falling from the sky would have a tremendous amount of energy asteroid the size of a house crashed on Earth at 30,000 mph.

Global epidemics

 A pandemic flu can cause a worldwide outbreak which spreads easily from person to person such as the Severe Acute Respiratory Syndrome (SARS-2003) , the bird flu (1997) and the pig flu (H1N1 flu virus .
Infectious diseases have shaped the course of human history Black Plague killed one millions European during the 14th century; influenza took 20 million lives between 1918 and 1919; the AIDS epidemic has more dangerous impact.
Emerging Infectious Diseases (EIDs) catalyzed by wars, loss of social cohesion, and natural disasters.
Prevention:-
 Public health education, isolation, sanitation, lessening congestion, closures, and surveillance .

Reversal of Earth's magnetic field -

 Magnetic field surrounds our planet like an invisible force field protecting life from harmful solar radiation by deflecting charged particles . But magnetic feild can be temporary and incomplete reversals. Reversal of the magnetic field won't be zero, but will assume a weaker and more complex form.

 Reversal of Earth's magnetic field increase risks for satellites, aviation, and ground-based electrical infrastructure. Reversal of Earth's magnetic field may led to the cosmic rays freely penetrate to the Earth's surface and cause mutations in living being.
 Rocks would reverse their magnetic field while cooling
Many animals are sensitive to the Earth’s magnetic field and rely on geomagnetism to aid in navigation. Depression and suicides will increase in the animals